I dont have time right now to resolve everything pending, so instead of posting in thread I'll just note here two things:
1. Warning: Pawetha that will incur an opportunity attack from the hobgoblin you formerly held hostage
2. Corban reaches the bottom of the stairs without being noticed (there's an archer at the top, but it will take spending your whole turn moving to get up there - is that the plan?).
3. Kaiakas has Advantage on that attack (for surprising everyone)