Minwu joins with like 350 HP or something like that, after you do nothing but some overworld trecking and a boss. Frionel, whose middle ground of the first three, has 40 HP at the start, and 10 Vit (so he gains 10 HP each time level gets boosted; yes, that's how HP growth is determined.)
If Minwu joins with anything but above average HP (let alone by a significant amount), you were grinding and abusing the system.
Similarly, if anything, that argument just helps Minwu; he joins with Swap, which lets him swap his HP scores with, say, Goblins, thus giving him a boost to a bunch of stats, HP and Vitality included.
Safe to say Minwu's pretty secure on HP.
Also, he's got Protect, though no clue what level and how exactly Protect works (Think its Defense+ some value multiplied by the spell's level? I base this off how Berserk seems to work on a similar logic for attack. It's significant, in any event, just rarely used in game cause its impractical to build up, albeit, for when he has it, its pretty impressive.)
