the way the final fantasys connect

[Masamune·1600]

I always kept thinking that FFIV and FFIX had similarities up the wazoo, but I once wrote a fanfic crossover FFVII and IX, where they were on the same world, just different times, and I didn't even know that VII's world was called Gaia. Though I do believe they aren't on that world. Sad, but true.

Simularities in all games include a magical girl heroine and a badass guy, plus a hero with some mental problems, a few none human characters -or at least someone not of the same main race on that planet, lots of battles, magic, summons, and... of course, the rabid fans.

There are numerous similarities to FFIV in FFIX, and even more and deeper connections to FFV. Beyond the more involved references in the links, there are scattered references to every FF title released before IX. That having been said, the references in FFIX are merely easter eggs, fun bits for fans of the series to pick up on.

Actually, there hasn't always been a "magical girl heroine'--in fact, there hasn't always been a female party member at all. Even if one ignores the question of the gender of the FFI White Mage, it remains that the Onion Kids of FFIII are male. I also doubt that (to say nothing of other titles) the Light Warriors of FFI had any "mental problems" seeing as they didn't have personalities or decisions or dialogue. There were no unusual race/non-human playable characters in FFI, II, or III, and Summoning was not instituted until FFIII.

I know that. I only said 1-6 so I can prove a point. I should've been more specific.

Yes, but the FF titles are only connected in the sense that certain concepts (airships and so forth) appear throughout the series. There is no direct literal connection--every FF is completely independent of the others.

FF VI don't have them either

I was still referring to just FFII and FFIV at that point, but, yes, this is true. I don't see that it helps the connectivity argument, though.

I don't remember either game mentioning this. Proof please

Neither game does. However, at the 2004 E3, SE gave away promotional pamphlets for Advent Children which refer to the planet as Gaia. The Advent Children Plot Analysis on GameFAQs includes a link to a scan of this pamphlet. Regarding FFV, while the planet goes unnamed in game, the OAV sequel "Legend of the Crystals" (the "LotC" I made note of in the first post) refers to the world of FFV as Planet R. As LotC was not made explicitly by Square (it was allowed and Sakaguchi and Uematsu had veto power, though), this designation can be debated. It was, understandably, worth noting.