Hello
I dotn really understand what you mean by "virtual image", if by that you mean vietual user (script) the answer is no, you cannot create 1 single script for multiple applications/products, each deployment is unique and requires its own srcipt, but that has no cost in terms of license, license matters for the type of virtual user and the ammount of vuser you run at the same time, so even if you create 1000 scripts it is for free, you can create script for all the protocols and as many as you need and it is for free, the license will decide what allows you to run from controller and how many, for reduce cost I ercommend you to go for VUDs (virtual user days) and to use preformance center, in general is much more complex and more expesive, but if you see the whole picture it will save cost, same with VUDs, answer for question 3 is no, since this is not possible.
regards