I really like Imoen 4 Ever because it allowed me to play without the pressure of rescuing her, and instead focus on building up the party for a showdown. This generally happens, but this game, my party over did it just a shade.
Sirene is a level 19 inquisitor, Isra is a level 18 Cavalier (no SoD), Jaheira is 14/14, Raesa (PC) is 14/17 M/T, Imoen is 17/10 M/T, and Mazzy is a level 19 fighter. They just wrapped up Watcher's Keep and the Twisted Rune easily. The latter so easily it surprised even me!
A nice arrangement of traps helped keep Shangalar off his guard, and a deva, a pair of werebears, and some elementals kept the back row from getting up in the party's grill too quickly. Imoen and Raesa were tossing breech and other protection stripping spells, leaving Isra and Sirene to clean up in front. The werebears went down pretty fast, but the Deva kept several of the bad guys busy until Vaxall folded. Once Vaxall went down, Shangalar (who was surprisingly easy to breach and impale) was next. He actually folded at the exact moment Layene got off her rather useless time stop - she did get off a gate spell, but the Cornugon she gated in was a bit too distracted to help her. Fortunately, other than a bit of crispyness, the Cornugon also went down fast.
So, I would say this party is ready to get on the ship and start the next chapter...