1st, wasn't Harry supposed to have mote than 1GF?
2nd, will Tom discover the sith and they're powers?
No, and no.
While there exists a slight possibility of H&Hr, gaining a second wife at the very end, as indicated in chapter two in the conversation between Charlie and Ginny, I haven't made up my mind. The same applies for Susan. Both are possibilities, but I really hadn't intended this to become a harem fic. Luna is already paired. For the foreseeable future, it will be Harmony.