Beautiful work Audrey!
I have been thinking about starting some heroclix repaints and would be interested in hearing about how you did them. Do you strip them down or just paint over. Some heroclix figures look like the paint is blobbed on and very thick. Also do you prime the figures? Any tips for working on heroclix would be most welcome. The weres you show us here look really great! 
Thank you. I have repainted Horrorclix, Heroclix, and Star Wars CMG figures. My process is basically the same and can be used for any prepainted figures.
First I clean the figure like you would any resin model. Remove any mold lines. Then wash the figure with dish washing liquid and warm water. I scrub the figure with an old tooth brush.
After that I remove it from the old base and but it on the new one. Plus I do any conversions at this time. Super glue and pinning work well with the bendy plastic.
Then I just prime the figure using Krylon grey primer. I find that if you let it dry over night it bonds better with the figure than if you start painting on it only an hour or so after it has been primed. Other than that I pretty much treat them like a normal figure.
I haven't really had any problem with the paint being in globs. Though at times you can see where some detail has been covered with the thicker paint they use. If a specific area is thick of globed you can always cut the paint away with a knife or file it off. I did cut the paint from around some heroclix figures as they just painted right onto of some mold lines so it made the fingers bigger. I trimmed the mold lines and excess paint off with an xacto.
The other thing is just the luck of the draw. For me I buy most all my prepainted figures off of ebay as I usually can get the exact figure I want for less than a $1 as long as it is not unique. This is easier with clix stuff since there are generally 3 bands levels of the same character. Just buy all yellows.
I hope this helps you out.