Final Fantasy challenges

[Ergroilnin]

Everyone know that playing most of the FFs is pretty easy, they were never meant to be that hardcore kind of JRPGs. So me and I am sure that at least few of you increase the game's difficulty by setting self-imposed challenges.

Of course some challenges simply make you grind more and thus aren't really that fun and enjoyable. I would love to get some ideas for each main FF about the enjoyable challenges.

Challenges:

FFI:

Well this one can be kind of unforgiving by itself but I guess either single stronger character or 4 white mages or something. 1 WM/Thief is crazy grind.

FFII:

I guess the best is just playing this one as it was meant to be? So no leveling up skills and abilities by prolonging battles, attacking your own characters etc.

FFIII:

No idea, I haven't ever played this one so far.

FFIV:

Not sure here.

FFV:

Not sure here either.

FFVI:

Never played this one either (do not kill me I plan on getting it done soon!)

FFVII:

Well single character or limiting materias (SC + enemy skill materia only sounds really interesting!) are obvious choices, anything else?
Initial Weapons.
no-materia

FFVIII:

Well not sure here, no GFs is pretty much limit spam so not very enjoyable.
Magic only run.

FFIX:

I loved level 1 game, it isn't exactly hard but it's pretty interesting imo.

FFX:

Simple NSG is great.

FFX-2:

Initial sphere dresses is perhaps the best not so hard challenge I think?
1/1/2 First Steps only challenge as well as the solo character challenge

FFXII:

Well I did play the original but I am curious about IZJS challenges?
Weak Mode
solo character challenge

I am going to edit this post with your ideas and I am really gonna need them since I do plan on playing through all the main games soon enough.