Well, looking at it, the class seems to only require one level of bard, meaning a sorcerer or wizard can get rather notable benefits for the cost of one caster level. Also makes me notice that while the class continues to get bardic music uses, it doesn't actually learn any new songs. That tends to make a few of the other abilities that have your bardic music interact with the dancing somewhat lacklustre. I'd suggest possibly dropping a level or two of casting progression and granting some progression of learning more bardic music.
Well, as you have it now, it seems to work reasonably well, as the deathwatch provides a somewhat intermediary way of identifying undead until you gain the ability to identify them even when not dancing with sense the opening door three levels later. As a side note, on sense the opening door, you change from second to third person partway through the new last sentence.
Owrtho