With a couple of exceptions, his builds really aren't that bad.
Some quick and genuine feedback:
FIGHTER 20/WM 7/ASSASSIN 3
Strictly inferior to the bard variant. You're losing a lot of spellcraft and a lot of skill points here. If you really want to do this for the RP, that's okay though, I guess.
Improved disarm is a poor choice for anything but large weapons. Grab some save feats or skill focuses (e.g. skill focus: discipline can be good) instead.
MONK 21/ASSASSIN 3/FIGHTER 6
I feel this one needs either epic dodge (to be a genuine dex tank) or more sneak attack to be viable. It's kind of sitting in the middle of the road, and not really impressing me because of it.
MONK 9/ROGUE 15/FIGHTER 6
You're looking way too squishy here. Trade some of that strength for con. Also grab some spellcraft. Your saves are dreadful.
Also consider trading some of those monks levels for more rogue (or even fighter). Six is plenty for cornersneaking.
CLERIC 21/FIGHTER 6/BARD 3
Don't build enough clerics to comment in depth, but note know there are a few flaws with this one. Extremely dispellable. No esf evo (though maybe not possible to get on a battle cleric without sacrificing too much). You're taking great strength I and not taking epic prowess, which suggests you could probably optimize your starting stats better.
FIGHTER 20/PALADIN 5/ROGUE 5
You don't need the dex. Cat's Grace is virtually undispellable by level 30. You could, however, use more con or even more strength.
FIGHTER 20/WEAPON MASTER 7/BARD 3
Too many save feats, IMO. Grab some great Post too long. Click here to view the full text.