ditto... I have seen your works and these are the pointers I can give you...
first, trim down the details you sculpted then then use a sand paper to smooth them.
second, try using smaller brushes for smaller details to make painting especially on the details more precise...
third, when there are detached parts that you can't place back properly (like shoulder joints, waist, head, etc), just use a super glue to fix it... you may lose the articulation but it's better than having a figure that has a loose part.
fourth, try to paint each part on its own (step by step) rather than splurging the fig with paint then painting the smaller details after....
fifth, give enough time for the paint and mold to dry (say, a few hours to a whole day, depending pon the brand you use), that way, the details you will make will not be destroyed...
I am not an expert customizer nor the better one, but I have learned all these pointers based on the mistakes I have done before...
I know how much hard work you have put on your customs and I can see your dedication... but there's always a room for improvement.
btw, Mary Jane is so cool, just trim down the belt sculpt and try retouching the paints... she will turn out a lot cooler...

The main I suggest from seeing all your customs is you should use WAAAAAAY LESS sculpting material. This figure would look cool if you used only a little bit of sculpting material for the belt. You might even try a very thin rubber band.