This is a late reply, probably too late to be helpful to the original poster. But I am playing through the OC now after haven't looked at it for many years, and playing a Monk. It is a very powerful character.
Still on list so still help anyone. Posting is good.
I started with Human with STR 12, DEX 16, WIS 16, all other abilities 10. Ability increases have been in Dexterity. Feats so far have been (1) Dodge, Luck of Heroes, (3) Weapon Finesse, (6) Weapon Focus: Unarmed Strike, (9) Blind Fight, (12) Improved Critical: Unarmed Strike. Skills have been Discipline, Heal, Listen, Persuade, Tumble.
Only use Listen/Spot in module you know has NPCs that use stealth or else wasted skill.
(I took Heal to use Healing Kits in combat without provoking attacks of opportunity. However, I think that using them leaves me flat-footed, which is very bad. So if I had it to do over again, I'd take something besides Heal.)
Skill still better than pots in battle cuz pot cause AoOs and can heal hench w/o them stop attacking for round to get their own AoO.
Right now I'm at level 14. Throughout the game, AC has been so high that even bosses have trouble hitting. I keep a stock of potions of Cat's Grace/Owl's Wisdom/Barkskin for the bosses, but in most cases that is overkill. CON 10 has been fine; with the high AC I don't need the extra hit points, and the Monk's defensive feats make Fortitude saves an infrequent occurrence.
I went with fists rather than Kama to make use of Stunning Fist. I haven't multi-classed, to maximize the DC on Stunning Fist and Diamond Soul.
If nice gloves in module it good choice. Fist do better dmg to skels than kama anyway.
StF DC have nothing to do with class lvl. DC is for character lvl so if go fighter 4 lvls, DC the same and get higher APR. Owl pots help DC, too. Main reason taking monk/ftr4 is feats and extra APR, but like you say, not need for OC.
My attack and damage are quite sufficient without adding in Fighter levels. I don't think it worthwhile to dilute Diamond Soul, which has had a huge impact. Though I carry Tomi around as a henchman, to detect traps and such, he is more of a liability than a help in combat, and gets a Stand Your Ground whenever I spot a tough looking enemy.
Try install that TonyK Hench AI for next time. Work much better but prolly need install from new game. Dunno for sure. Can use hench inventory in OC if you want, too, but don't have to. Yah, monk SR is nice to have... very nice.
The only problem with the character is that Monk Speed is often more of a curse than a blessing. I have to be careful not to outrun Tomi's range for detecting traps. At one point I dumped Tomi to bring along Sharwyn, but it was too easy to run out of her Bard Song radius when battle starts. (i don't want henchman who are going to fight in melee- my Monk is such a good tanking character that I don't want henchmen unnecessarily drawing attacks away from me.)
Yah, speed sometime hard to control. Easy way just do detect mode when have haste robe or boots. Then see traps pretty fast. Or put many point to Search so don't need so many rolls to see them. Think dice rolls per 6 secs not in detect but per 3 secs in detect plus distance when dice start to roll is double in detect so that what a fast monk need to see trap.
Maybe try Glinkle if toon good tank. He stay back far enough. But spend lot of his time buffing. Still, should try all for a little time just to see what work best with tanker monk. Some archer work but when I play fast monk in OC I always lose Sharwyn and need to reload so she come back to me.
Dex build good for monk cuz when it see Mestil or Element sheath can switch to sling with high AB still. No monk APR with sling but also no dying from hitting too much acid dmg in one round. Or just wait til dmg shield expire if you will wait around. Slaad make bad Mestil dmg usually.