Now that I've had a chance to sit down and read through the player's handbook, I've noticed a couple things that we were either doing wrong or that I wasn't aware of, along with a few other points of interest.
1-Since Ucoy is an artful dodger, he should get an AC bonus equal to his charisma modifier against opportunity attacks. I don't know if you were including this or not, but I didn't know about it before now. My new character is also an artful dodger, so I'll have to remember this. (Rogue Tactics, pg 117)
2-Doing a sneak attack, using an action point and then doing another sneak attack doesn't work, because you can only use it once per round, and using an action point doesn't create a new round. (Sneak Attack, pg. 117)
3-Ucoy should have gotten a +1 to hit with any attack using a dagger because of Rogue Weapon Talent. I don't think we were including that in his attacks, but I'm not sure. (My new character wields shurikens, so he'll get to use d6s instead of d4s from the same class feature.) (Rogue Weapon Talent, pg. 117)
4- When Ucoy and Faicon assassinated the sleeping Goblin Chief, they did more than enough damage to kill him, since a coup de grace results in an instant kill if the target takes damage equal to or greater than its bloodied value. (Coup De Grace, pg. 288)
5-Another point of interest - once per encounter, a character can gain combat advantage against an adjacent enemy by making a bluff vs. insight check against the target as a standard action. This could come in handy for a rogue, so I may take this instead of one of my other skills.(Bluff, pg. 183)
I think there were a few other things I noticed, if I can remember what they were, I'll post them here.