[Chivas2973]

the vault can be edited but they don't advise messing with it, that is why it says at the to DO NOT EDIT, but if you do, the server needs to be off or it won't work, once off, find the number that represents the xp and edit it, but do this at your own risk

a few ways to make heros only accessable by you or admin, 1) freecode posted the code to make a hero admin only in here, but it requires some knowledge of coding
2) open the sma for uncle sam and figure it out, also requires coding knowledge
3) the simplest way is to make a 20 level server and make levels 18, 19, 20 such high xp that nobody could ever get and then make the cvars for the 3 heros you want fit that. 1 hero level 18, 1 level 19. and 1 level 20, now give yourself level 20 and you can get 3 heros nobody else can