I would tint your silicone flesh tone and keep the painting to a minimum. Sometimes paint can flex off of a prosthetic and if you tint your silicone you would have better results with the color staying. I usually mix some silcone in whatever color I want (say your reds and blood for the inside carving) and paint it on so that it forms a better bond.
I'm not sure about using latex to attach the prosthetic, I've always used prosaide or spirit gum to attach with and I'm not sure how well latex and caulking play together...Allen would the the man to ask for that.
Also I've never carved and transferred in the manner you are planning. I sculpt with clay and then cast in plaster, which isn't as time consimng or hard as it sounds. Also, it might be easier to just put the silicone wet directly on your skin, smooth it out with the edge of a popsicle stick and when it starts to tack up, carve your number 13 into it. It would seem that would be less time consuming for ya.
Good luck to you!