In my opinion, those stats are even still a little underpowered. I'd tack on an additional three or four million hit points to each of the final bosses. It would give players a little incentive to get up in the higher levels.
I've already did this in a scene.bin that I made for myself. I gave Jenova*SYNTHESIS about 15,000,000 hit points but little stats. The battle freaking dragged ON. I had it set up, though, so my characters had 255 of the main stats, so it wasn't the damage that mattered, it was just because the battle just dragged on. Bizarro had like 1,500,000 credited to each portion and like 2,000,000 to his core. And then Safer had, I think, 22,000,000 but I didn't bother finishing him. I had already been fighting for a good half hour, no joke.
For some reason, I also made First Class SOLDIERs extremely difficult to kill. Lots of health and strength. I like First Class SOLDIERs.