While I know nothing about creating trainers, on seeing this thread I played around with the saves and managed to alter both Cliff and Sheryl's HP to 200.
If the two of them you've found are the same to the ones I've found, the first (as I've found them anyway) is current HP and the second is maximum HP. I tried changing just the first and had a Sheryl (Lvl 11) with 200/117 HP.
I don't really understand the whole addresses bit so I'll post a screenshot as well. Cliff's HP is on the 00000420 line, 10th is current and 14th is maximum. I'm using Hex Workshop. Sheryl's is on the 00000480 line, 0 as current and 4 as maximum. I've not looked at any of the others. All I did to modify them was edit them and save the file. The file is Save00.dat.
Screenshot of them with 200HP at level 11: http://i19.photobucket.com/albums/b198/ ... exEdit.jpg
Screenshot of how I did it: http://i19.photobucket.com/albums/b198/ ... diting.jpg
I haven't checked to see if it'll work in battle beyond just killing a couple of Medusa and making sure it didn't crash or if it'll automatically go down to what it should be when you level up.
(Added at last minute: On the same line as Cliff's HP, 00000420, 12 and 16 are his Force, I assume 12 is current and 16 is maximum but I changed both to 200 at once and it worked fine.
Edit again: Screenshot of Cliff with 200 Force - http://i19.photobucket.com/albums/b198/ ... xEdit2.jpg
Kitty's Force is 000004F8, 2 and 6.
Does any of this help at all? If it doesn't help in making a trainer, it might help a few in being able to edit it themselves at least.
Yet another edit: While you can edit the force to be as high as 255, as soon as you get into a battle it'll go back to
0. So no constant dual attacks on the final boss. Whenever I try put the HP above 255 (FF) I'll usually get an extremely high number even if I only put 300 and the character will start the battle dead, even if it works on the status screen.
And again: Cliff's Units are at 00000438, column C. I just did a quick test and changed his 7 units to
, then to 255 and filled everything up with 100+ left over. Mena's Units are at 00000468, column 4. Changed to 125 (7D) since that's enough to fill up everything and over. 000004B0, column C is Aoi's. 000004E0, column 4 is Lucy's.
By changing 000004C8, column 4 from 05 to 06 I somehow replaced Lucy with Kitty. See here for screenshot: http://i19.photobucket.com/albums/b198/ ... NoLucy.jpg
It's untested so far though. I've not tried getting into a battle or anything. (tested and works but character picture doesn't change, only sprite does). 01 - 04 removed the character, 07 changed Lucy for Will (who comes in as level 30 but is actually about the same power as the rest of them, his HP goes down to about 60), 08 Iry who's about the same as Will, 00 freezes it and I couldn't find Sheryl.
http://i19.photobucket.com/albums/b198/ ... oLucy2.jpg
http://i19.photobucket.com/albums/b198/ ... n/Will.jpg
Maybe if you find out some way to alter the hex code in a save file automatically, you could use that for a trainer and have it alter everyones HP/etc as well as give them full units.