Just reading about this ultimate seems pretty crazy, so much stuff to do.
Ultimate Dispel AND the inability to use a support (at least well) sounds horrible.
Also I'm not sure how much Blind I really need, honing Blind Shot takes some very valuable Lightning Orbs :(
The difficulty is going to depend on how much you got going for you in the form of SB/SSBs and hones and what buffs you can bring to the fight or how strong your AoE is, if that's your thing.
Her Ultimate dispel shouldn't pose to much of a problem if you focus target her first.
As far as blind shot, I only brought 4 shots and only 1 of them missed. You want to make sure your first shot lands on Logos asap. As far as dispel/banishing I only needed 4, but if you're going aoe, maybe 6 uses may be needed depending on your party buffs.
Again your mileage may vary, I came into the fight with 2 SSBs so I didnt need much in mitigation outside of blind landing and just killing leblanc in a few turns and instagib-ing Logos in 2 rounds.
This fight is much like Gigas U, in the sense that as soon as one dies the fight becomes much easier and more manageable especially with blind/slow on them, although 10 times easier than gigas since a lot of the mitigation is getting blind to land on logos/Ormi and slow on leblanc/ormi.
An alternative could be going full magic if you have good mage/sages with powerful staves. Meteor/Ruinga/Maduin/Valefor/Bahamut would make this fight very easy, and you use Yuna's BSSB as your RW and let your strongest 2 mages pop them and spam her aoe command(attack iirc). With proper buffs you should be doing about 4800-9k per shot aoe. You should be able to chip about 3-4 turns per char, so roughly 30/40k -70k per character... worse case scenario 28800-38000 aoe if your mages are lacking gear/levels/SB/ssb buffs. If you dont have any good 5 star staves/faith/Devotion, probably not something to try.
