Angel, Those putties should work just fine. You might want to take a look at Jerry Rutmann's hair sculpting/addition techniques for inspiration. Here are some examples of his work:
I've used a hot knife (pyrogravure). This only works on plastic heads as the heat will not cut through a resin head. You will also need a heat control, because at full heat the knife will melt right through the plastic.
I am new at sculpting and would like to know how do you sculpt a moustache and head hair at 1:35th scale?
Up til now I have fixed a nose of a resin head which didn't come out because of an air buble and came out pretty well (at least I am happy with the end result).