Yes, I use Platsil Gel 10, it's a two part mix but there is a 3rd part you can get called 'Smith's Deadener' which will make it softer and stretchier if you want or need that. But that mostly just used for prosthetic make-up appliances.

You can paint it with another silicone called 'Psycho Paint'. That's great stuff because it has a long cure time so you have a lot of time to paint and you can thin it down enough to airbrush it.

Platsil is a translucent white rubber if you don't tint it and both the Platsil and Psycho paint can be tinted with acrylic paints. There are special tints made just for silicone (Silc-Pig tints) and they are better than acrylic but MUCH more expensive.

Yep, Ultracal 30 is fine - I'm using it for a casting right now actually. You can spray it with 'Mann Ease Release 200' if you want the mold to have a longer life but, a release really isn't necessary. :)

You can do it either way but, I always paint a skin into the mold parts first before filling. Filling can be tricky depending on the shape of your mold and how to fill them is something I decide on a case by case basis - there's no 'one size fits all' method.

You can only paint silicone with more silicone so far as I know. What brand of silicone do you have? If you say it's blue, then you probably have GI-1000 or some similar silicone and that's a tin based silicone - not the best for casting puppets with, that's more of a mold making rubber. You CAN use it to cast with but, you're not going to be able to paint it or glue it and it's a tougher rubber that silicones like Dragon Skin or Platsil Gel 10 which are softer and paintable.