[@KoL][@Corporal Lance]

Ryu had pretty much answered the basic gist of the issue regarding recurring elements; now that I'm fully awake, I shall do my job to elaborate further on what we the GMs have discussed, and also some thoughts I have:

[b]1) Recurring Characters i.e. Cid, Gilgamesh, etc.[/b]
While they may appear in almost all of the games so far, these recurrences do have features that change from one game to another or things that make them unique and easily identifiable to a particular title, which you should be taking into account as you develop your miniworld.

[b]2) Recurring Creatures i.e. Moogle, Chocobo, Cactuar[/b]
For this, please check the Terminology section in the IC tab.

[b]3) Recurring Summons i.e. Bahamut, Alexander, etc.[/b]
We have decided to employ the "temporary contract" system from [i]XII[/i] and [i]Type-0[/i] rather than allowing players to /own/ the summons permanently as seen in [i]Lightning Saga[/i]: your character can call them forth via a Summoning Ritual by offering something of similar/equal value before they can lend you their power for a limited time duration, after which the summons will return back to the void they're originally from. As for their appearance, to avoid unnecessary debate just think of these summons are nothing but shadow silhouettes while retaining the basic form to tell them apart from each other e.g. Alexander = castle, Odin = demonic knight on a six-legged steed, etc. If you reeeeeally want to go into the details, you can assume these shadows can shift their look to the character's understanding (something like how the Greek goddess Aphrodite constantly changes her appearance to appeal to those who set their eyes upon her).

EDIT: I've added these into the FAQ.

MORE EDIT: An add-on. See below.

[b]4) Recurring Weaponry i.e. Excalibur, etc.[/b]
Regarding character's weapons (or equipment in general, including accessories and whatnot), I'm not expecting you guys to stick to the game system literally where your character has to grind up the level and swap out a new weapon each time; as mentioned in the CS Form, you are only required to list down the equipment and abilities [i]unique[/i] to the character you're playing (read: your character's signature weapon, power or whatever that define/specifically associate with your character, not those common stuffs that are obviously recurring across all the games).