oh shit we talkin gameplay in jp here i am all over this shit
I have no idea how you're struggling with U+ content with both Shout and SG, HotF, and a BSSB (even if it is Tidus's... excuse me, Tiida's. Haha what a stupid name for a stupid schmuck). I'm not even saying this to be insulting, I literally don't understand where you're falling flat. Granted, U+ Bartz was kiiiiiinda insanely difficult, and I had Bartz's BSB and great 5 synergy, so maybe I can see that. I know you're considering your Global account your main, so do you just have really bad hones or something?
As for Ifrit, bring a spellbladers with Blizzaga/Blizzara strikes, Ramza on Shout/Breakdown duty, Tyro and Yuna on Heal/SG duty, and if you can hone it to R4 and have a L80 monk, bring the monk's ITD attack for your fifth and you should be able to pull it out. The Monk skill is especially good here, L80 Jecht was cranking out 6-7k damage a hit after boosting with that, and a 4++ FF8 dagger. This exact setup almost worked perfectly for me, but not having a native Wall OR Shout meant I couldn't quite pull it out. You're well equipped enough that this should not be an issue, barring your hones being terrible.
He doesn't have any water weakness (ice only), so Tiida's BSB won't really be that useful aside from burst damage, and you'd frankly get more out of bringing, say, Squall with two Blizzara/ga strikes even if you don't have a relic for them.
One thing I've realized, especially in this fight since Ifrit's defenses are so insane, is that the Damage +20% record materiae are leagues ahead of the ATK+10%/ATK+20% ones, so a diversity of good weapons here with the relevant RMs will help too.
You may want to go back and look at my most recent attempt at offing him like a month ago? The Beatrix tank build won't help you, but the one I was trying with Jecht should flesh out more of what I'm talking about in this post.
EDIT: What do you have in the way of FF8 synergy? If you have good mage equipment for the realm, one thought would be to have Rinoa's BSB as your RW (since you have the native trinity) since it's all ice elemental attacks. I think Lulu's new SSB also has En-freeze, alternately. If not, I'd recommend actually bringing in another shout, so you can have Ramza do both Power and Magic Breakdowns, and have Ace Striker as his RM. SG and Ace Striker on Tyro is another viable option, and in that case I would prioritize Magic BD/Indoor Spell over MBD/PBD.
In addition to 8 synergy, aside from the trinity, what SSBs or recently-released SBs do you have? If you list those out I can probably tell you what team I'd use.