The easiest way to answer all of this is to beg IS for an FE7+6 remake. They could pull an FE4 and do a generations thing (Roy's base stats are such and such because his mom was an ice dragon, for example), and maybe finally include the FE7 cast in FE6 lore (as in Sue actually mentions Rath).
Edit: Oh yeah, and the FE6 cast can finally blink.