I'm glad that your research has corroborated my earlier suggestions. You may want to give my
UI suggestions wall of text a skim again, as I did a bit of analysis on how to deal with not displaying all the stats at once. The character stat window draft you're making now doesn't seem like it's made for a static-ish window. I recommend working within your full mockup instead of making it separately.
The games that don't have health displays on the battle screen show a different sprite when the character is below a certain amount of health, so they do have an indication of characters that are near death.
Keep in mind that Disgaea has health going into the
millions and damage is randomized. There is no precision with numbers in that game. It's also 3D so you can rotate the screen to see parts of the HP bar that are blocked by other characters.
I think having the character fill up with red would be pretty good if changing the sprite isn't an option. However, I'd much rather see a more "themed" approach to showing battle damage on each character. Since they're miniatures, you wouldn't have them change pose, but could instead have things like paint peeling and gashes in the plastic. It's more work, but it's the sort of thing that makes a game feel like the creator loved it and so should the player. This could even be done procedurally, without having to pixel individual damaged sprites for each class, you could define spots on the character sprites for damage sprites to appear (or, if you can find the common shared silhouette between all your classes, you can just spawn damage sprites within that and not have to worry about defining damage points individually for each class).
I'm going to withhold my feedback on numbers for now because I feel that you need to work on the character stat window in context, and may thus find a different arrangement of stats more effective.