I posted this on reddit in /r/ffxi but wanted to post it here too. Visit the reddit post for updated info if any edits are made, in case I don't edit this post as often.
Q: What is FFXI Mobile?
A: FFXI is coming to mobile (Android, iOS) around 2016. To quote SE (Square Enix):
Q: What regions will FFXI Mobile be available in?A Native App Project Providing A Full-Fledged FINAL FANTASY XI Experience on the Mobile Platform
A: Japan, Korea, North America, Europe and rest of Asia. Quote SE:
Q: Who is developing/publishing it?We plan to extend service to Japan, Korea, and North America, as well as Europe and the rest of Asia
A: Square Enix (FFXI dev team) and NEXON, Co., Ltd; SE will still be involved, quote SE:
Q: Is this the same thing as Final Fantasy Grandmasters?Basically, they [FFXI dev team] will take part in ways that make the game "FFXI-like" such as planning, how the game works, lore, and editorial supervision.
A: No. While Final Fantasy Grandmasters takes place in Vana'diel, it is a different game and is not FFXI nor FFXI Mobile. Grandmasters is a spin-off currently available in Japan on smartphones (see /r/ffgm).
Q: Will FFXI Mobile share servers or existing characters with the Windows version?
A: Unknown. A relevant note, according to these quotes from SE:
Q: Will it be free to play?it will not involve directly transferring your character data over, so it’s best to think that a new, separate account and character will be used to play [...]
...
Currently, I’m unable to say anything definitive, but as a game, it will be something completely new.
A: Unknown. Quotes from SE:
Q: Will this launch with all the FFXI expansions?We would like to have as many people play as possible, so we believe it will be a system that will allow players to participate with ease. You could say that it depends on the business environment at the time of launch. For example, when considering that a method of payment is unimaginable at the stage we're currently at might be proposed, it is not possible to make a conclusive decision.
...
Unfortunately, it’s still too early to comment on this matter. But, we will consider methods that would make it easier for players to join and continue to play.
A: Not at the start, no. Quote SE:
Q: Does this mean the game will launch with CoP era?There will definitely be restrictions on content and jobs at the start, such as only implementing up to Chains of Promathia.
A: Unknown. SE says details aren't concrete yet. It's unknown if level cap will be below 99 at launch.
Q: How will such a large game (hard drive storage space) fit on a phone/etc?
A: Unknown. The PS2 version for example is a bit over 5GB in size. Considering Star Wars KOTOR on Android is 2.4GB, it may be feasible for a 5GB+ game to be on the app store. SE is planning for seemingly all expansions after release:
Q: Will it still be the normal interface/client?Players will eventually be able to play Rhapsodies of Vana’diel, so we'll be putting in a ton of effort to try and match or even surpass the PC version.
A: No. It will be a native mobile app, built from the ground up. The interface will be designed for mobile.
Q: What will it look like?
A: No specifics yet, but SE has stated:
Sources:[...] the idea would be more along the lines of a further refined FFXI given the high-perfomance mobile devices available today.