Hey...
Hey Macbrander. I've brushed latex over foam many times. Personally, I don't think it has the right look for human characters. It's better for creatures, ogres, etc.
If you want to use latex for human characters, to achieve the best look you'll probably have to go through the whole process of sculpting, mold-making, casting the latex and foam (or patterning a sufficient foam skull), and so on. That way you get a smooth surfaced latex covering - more like human skin.
I'd really consider whether a realistic look is absolutely necessary to the character. It may be, so in turn, the work involved would be necessary. If not, you may have an easier construction experience and find that in the end you sacraficed very little or even nothing at all in terms of the character.
Hope this helps!