Hi tsmall. I'll try and answer your questions as best I can. Pluto symbolises primal survival instincts - the sense of jungle law, survival of the fittest. Ultimately its a collective symbol, like Uranus and Neptune, and is concerned with the survival of the species or tribe. But it brings a life-death intensity to the personal of chart factors which it touches.
A couple of questions here? First, what is your opinion as to which planets constitute personal chart factors? I ask because some modern astrologers only count Pluto as being personalized when aspecting the lights, while others seem to include it's aspects to all the planets between the Sun and Earth (Sun, Moon, Mercury and Venus) and still others include everything out to Uranus. Secondly, I remember reading a long while back that often we don't see the effects of the outer planets until after the native has experienced their Saturn return. Something about the lead sheild of Saturn protecting them?
Mars opposite Saturn obviously has fears that the will won't be strong enough to conquer life's obstacles, including those imposed by authority figures. So Mars in this chart is very sensitive to feeling thwarted.
That's an interesting analysis of the aspect. Is that a general idea of Mars opposing Saturn? i.e. the fear or uncertainty that the obstacles will be difficult to overcome? As to "sensitivity," do we want to consider that Aquarian Moon in this instance? I'm looking at that retro Mars in mutable fire, giving it heat and volitility (mutable) and a level of "unpredictableness" that might have a hard time knowing when and how it is and is not appropriate to express itself. Saturn in this case seems to have the upper hand so to speak, because it is in a stronger positon--in sect, rising, and the triplicity ruler of all her Gemini planets, as well as the ruler of her Moon. What's more, it is by far the most dignified planet in her chart as both the Lord of the Geniture and Almuten of the Figure. So Mars in this case is sensitive to having his will thwarted, and acts out in temper, but with Saturn in strong position, the opposition could indicate a need to balance restraint with action, with Saturn's restraint ultimately able to "win?" Saturn represents time as well as authority, so perhaps given enough "time" she will learn how to internalize the ability to do this balancing for herself, and channel that Martian energy into more creative persuits?
Pluto getting involved ups the stakes so that it becomes a felt as an issue of life or death. Pluto brings the wide Mars Saturn opposition together, too, by being in closer orbs to Mars and Saturn, though I don't think it quite squares the Mars/Saturn midpoint. The transformative power of Pluto feels very threatening to the ego, especially in a child. Some children would bury their will for fear of being destroyed or of destroying others. It seems that this child does not do that, but rather fights for her life where matters of will and autonomy are concerned. There is tremendous pride contained in this aspect (especially with Mars in fire in the 5th house) - we probably can hardly imagine how painful it would be for her to yield to the will of another. Hopefully at some point she will gradually learn this lesson, but what definitely won't help is heavy handed authority.
I absolutely agree about heavy handed authority, but it has to depend on what the definition of "heavy handed" is. In Sydney's case, this aspect seems to be saying that any authority that opposes her will she will see as being heavy handed, but that the authority/restriction/responsibility Saturn gives is what will help her control her anger. I'm not so sure about the fighting for her life part, or the idea that we can't imagine how emotionally painful these encounters are for her. It sounds a bit like you are describing the fight/flight syndrom here, which makes some sense. As far as reacting when her will is being challenged, I see that sensitivity of "will" coming from her Cancer Sun, and even though the modern aspect showing between Sun and Mars is an inconjunction (which traditionally we would consider as the inability to witness each other,) as I pointed out earlier Cancer and Sag have the ablility to "hear" each other. So Mars "hears" the Sun, and reacts accordingly. That they hear and don't see could indicate why even she can't consciously explain why she gets so mad and reacts the way she does.
Moon in Aquarius usually instinctively responds in a detached and civilised manner, which is partly why I put about the strong social orientation. Its conjunction to Neptune suggests a deep yearning for a sense of belonging which I felt might cause her to suppress separating emotions like anger when I first saw the chart. Saturn and Venus in air are aware of the importance of civilised behaviour, especially in the 11th house, and the trine could be seen as creating a comfortable cussion of social inclusion out of these 4 planets. But it seems from what you've said that she does not suppress her anger in the name of inclusion and civility.
This made me laugh, not because of what you have said, but because of Sydney. I think her Moon in Aqua does make her detached to a certain extent, in that things that would bother another child just roll right off her. As far as social inclusion goes, she does want to be included, but often has trouble distinguishing what would be considered socially appropriate behavior for that which would not. (Think manners here.) It's as though she is who she is, and is ok with the idea that other people might not like her. Like I said, she marches to the beat of her own drummer.
So two further thoughts come to mind about this configuration. One is that trines in air can be quite opinionated, and there are lots in this chart of course. The other is that Moon conjunct Neptune in the 7th might be angry that an anticipated perfect ideal of loving connectedness was not found to be manifest in the real world. I think the weight problem could back this idea up too. She may project Neptune and see others as weak and insufferable when compared to her preferred combative approach.
I'm not so sure she see others as week, though I know for a fact she finds her sisters insufferable. 
Sun in Cancer in the 12th is interesting. The Sun is the planet with the power to orchestrate the rest of the planets into a unified whole, conferring a capacity to find joy in being oneself and pursuing a unique destiny. With the Sun lost to the 12th, perhaps she lacks a sense of validity and worth that could loosen the grip of her combative reality. This placement could also contribute to the eating issues. The quincunx to a fiery Mars suggests that her sense of Solar weakness may nag at her, perhaps compelling her to prove her potency and autonomy, although on first seeing the chart I thought that it would contribute to suppressing the aggression of Mars.
I wanted to take a second here just to say that her weight issues are not as a result of over eating but rather genetics. Sure, she enjoys food, and cooking (which she has recently started learning to do) but she does not eat anymore than her sisters, and they do not have weight problems. I wrote a whole blog post about it elsewhere, but there is something (perhaps a detrimented Jupiter ruling a retro Mars) that both causes her to be what we consider overweight and reduces her stamina for physical exercise. I say this because even when she was a toddler she didn't have the energy most children that age do. When other kids want to run and jump and just go, she would tire very easily.
Taking a long time to do things could be an act of defiance, rather than a distractedness, or perhaps she decides to indulge her curiosity just when someone needs her not to!
I absolutely believe it is the second and not the first. She isn't a particularly defiant child, though the teen years are coming, but rather she wants to stop and look at everything. That Gemini mind is very easily distracted.
And I feel that Syd (sorry I've only just registered that this child is in your life and that the name has been included) just
has to be heard. I get the sense that Syd will explode if her opinions aren't heard. Of course she needs boundaries too, and ultimately must enter the burning ground which the alchemists called the 'Calcinatio' so that these primitive desires for power and control can mature into a solid sense of self that can function in the world. But this will of course be a gradual process with Syd being only 10. In the mean time careful use of words, eg. 'Yes I can hear what you're saying. I'm not saying you're wrong. But today we need to do this. I'm sorry if that's frustrating for you. Will you help me plan things, please?' Obviously you'll know best how to communicate with her, and it won't work every time, but it might help.
You are absolutely correct here.
One more thought - the Leo Ascendant may manifest as an awarness of how she wants to shine her light into the world but can't yet find it, so she performs to get attention instead??
Yes, and who knows, maybe she'll be a rock star for real.
I'm happy to carry on discussing Syd's chart, and don't mind debate/challenge also!
