In regards to repro in general, they sometimes offer a "better" translation than the released games. Fan translations usually include more language specific phrases and meanings that are lost in trnaslation with some games. A classic blunder being "All your base are belong to us". This is a result of a "direct" or literal translation as opposed to a context translation. Lots of NES games are famous for these bad translations.
As for FFV, the PS1 port is pretty lousy in my opinion. It has really long load times and the translation isn't very good. The GBA version of FFv Advance is great, with a much better translation. I am not sure how the repro cart holds up, but it has to be better than the PS1 version.
To play GBA games on your TV you need either a Gameboy Advance player for the Gamecube, or a Retron 5. Both will play any gameboy/gbc/gba title with no problem. Not sure about DS. There IS a way to hook it up to a computer, but I don't know about TV.