Pluto is the higher octave of Mars, or it basically acts like Mars, but in a weird way since it's past Saturn *gasp*. You don't need to have a good Mars to have a good Pluto, you just need to look at Pluto and dignify it as if Mars was in its place. I don't think mutual receptions apply here since Pluto doesn't actually have rulership to be able to deposit to be in a reception, but everything else I can think of does. Your Mars being in Libra has nothing direct to do with your Pluto being well-placed.
The thing with Pisces is interesting. I've seen that a lot, but not on everyone, so it's not necessary to have it, and I don't even know why it happens a lot. It probably has to do with Jupiter and Venus being the planets of luck and both dignified in Pisces. The Moon rules the Earth triplicity by night and the sign of Cancer, which is the exaltation of Jupiter. The Moon in Pisces is in its triplicity. Hmmm...
Look at your 13th harmonic, superimpose it onto your natal chart, and if you have a talent triangle with Pluto as the apex (two sextiles to Pluto and a trine between the other planets) then you have what I see on a lot of famous people's charts. I haven't actually done that on a whole ton of famous people's charts as it takes a little more patience than I sometimes have, but I've seen it on all the ones I've done it on, so it has to mean something.
@dprez - That's prominent but not in the same way as I've seen. I'd have to go analyze the thing to tell. As I said, harmonics and stuff.