The World of Avlis

I know the answer to number 1 is yes. Once you have 21 total levels, you are epic. This still only counts towards general epic feats though, since you are not epic in any one class until you reach 21 in that class (or 11 for PrCs). So epic skill focus should be open at level 21 if you have the other...

I think the blackguard is the holy warrior of Maleki, so you have to be both CE and worship him in order to get the PrC. There are other PrCs for other evil gods though.