Interesting. I also have South node conjunct Sun, and in addition my North node ruler is my sun, plus a stellium around my South node, so this whole theme is central to me. It may mean that your south node habits are doubly emphasised and it is even more likely or often that you slip into them- that said, the Nodes are a balance so, as people have said on my chart, maybe there is still unfinished business, or karma if you see it that way, with the south node.
You have a similar ascendant to me, with a Gemini 8th house and vertex like me. It seems significant that your Vertex(v. important point IMO) is conjunct your sun and south node, this is a fascinating aspect because as I see it, the Vertex is clearly the positive development with the Vertex/Anti-Vertex polarity. And it's conjunct your SN. And yet, the NN is the positive development with the nodal polarity, and it's conjunct the Anti-Vertex.
This would seem to require very delicate balancing and seems to represent being pulled in different directions for evolution, like it's predestined.
To me the Anti-Vertex is more negative in a more fated way, than the SN, whose habits you will always display to some degree. So it's better that your sun is conjunct the SN and Vertex in my view, means go with your natural character and temperament, but don't fall into the lower expression of your sun/SN sign(there should be reading on that on the web)- so I'd say your NN is about maybe diverting and evolving the expression of your sun and SN, and maybe it also indicates that there are some tough fated experiences(Anti-Vertex) that will be necessary for growth and development.
As for the sign and house placements, Gem 8th is a detail orientated, forensic, curious, and more dutiful(though still mutable) sign in the house of deep connections, hidden research, transformation, shared resources. So Gem in this house would seem to be a very journalistic, forensic sign in terms of research on hidden subjects or 'Plutonic' subjects. One possibility.
Sag 2nd, more in the case of the anti-vertex(from my experience with this position) would seem to be about the problem of being too big picture, over-confident/expansive, unreliable, feckless, with personal resources, security, self worth, desires and attachments.
However as I say in the case of the NN being conjunct it might mean you will grown and learn from this crucially. Maybe lessons over resources and worth?
The polarity seems to be details and lower mind in shared connections/resources vs philosophy and big picture, and abstration in personal resources and perception. Still working on understanding this polarity as it is key in my chart.
Sorry if I digressed a lot there, hope I covered the conjunction, but I couldn't help noticing those fascinating traits in your chart and thought I'd try and interpret....