Thinking 3 seems high, but I have no idea how an Auto-Life+Reviver combo works out. Unfortunately, everything else is kind of meh. Chakra is horrid until disk 4 (Although 20% MP healing might have a use). Endgame FF 9 armors help against elemental blitzes, but minus some notable matches, those aren't scattered everywhere. No status immunities to most people too. On top of that, most of his decent skills come on disk 3, meaning by dungeon rules they'd probably not kick in for quite some time even though they don't come that long after he joins. His ranking really depends on that, because if he gets those skills around floors 4-5, he's going to be ridiculously slow starting for a 2.5 (And not completely owning after that). I mean...I'd probably say he's better than Quina, but Quina seems like she'd be a bad 2 anyways.
Kurando...is more solid than I would at first think, since SP would reset in between each battle right? Resources aren't deep, but 170% speed after transforming (Might be closer to 150% when first obtained?)+solid physical damage. Again, he can get the healing about 2 seconds after you get him, but I don't know if that means he could get it pretty quickly in dungeon.
0.5...could actually work for Larsa. Free full healing is nice, but it's ST off a tad below average speed (And 85% by the second time he comes around). And by the second time you have him, he has like 1/2 average damage, and 70% HP...and I'm not sure that factors in HP+ Gambits. If Rand is in 0.5, not sure I could really justify Larsa as better. Similarly, hard to look at Larsa and see someone as good as Rena, Mint, and Restore Aeris, who are all 1s. And he probably just gets relatively slower and less durable and less damaging as the time rolls on.
Shana/Miranda are really bad dungeon wise. No Dragoon until mid disk 2, and then what that's obtained, MP is limited and I believe their SP is tied to Dragoon level. Bad SP at first is really atrocious, meaning not only do they need several turns to build up Dragoon levels, but they can't really store the levels all that easily either. Most turns are going to be spent Defending or trying to inflict 25% Confuse, because the majority of the time they might not actually have anything more worthwhile to try and do. With magic items this would be a different story. Speed and Mdur are nice, but so many other things are working against them. 1 might work, but 1.5 seems high. Not really sure anyone besides Rose works from LoD since they either lack team options, or have Meru's Mdur.
SO 3...skillsetwise, they have solid potential, but not quite sure how well SO 3 would generally work those. Adray over Sophia for sure though, since joining much earlier makes her nicer dungeon interps (For all that Adray in dungeon would feel like a stock healer/reviver, I'd imagine. Easier to get one of those without interp mess). I could both see the worth/uniqueness in Maria/Peppita.