I now own every non-mmo, non mobile, Final Fantasy game and their sequels. Except for a few. I don't own Revenant Wings because I'm not paying $30+ for it on amazon and it was only ever released on DS. I don't own Crisis Core because it is not available digitally on the PSP so it can not be backwards compatible with the Vita, since the Vita uses cartridges and the PSP uses discs so it's only backwards compatible with digitle PSP games. And I don't have Derge of Cerberus because it's only on the PS2.
Seriously, they call the FFVII sub-series the "Compilation of Final Fantasy VII" so why not make a collection like one of those Kingdom Hearts collections with VII, Crisis Core, Dirge of Cerberus, and Advent Children in it. Easy money.