I'd do ONE flavor with alcohol - something really tasty, like Midori or Chambord. That way you don't OD on the alcohol. Make a test run of the cubes a bit in advance though - sometimes liquors don't mix well with the jello.
Sounds lovely to me, and I'd enjoy a piece. You might want to call it something different, though, with liquor involved - tipsy cake comes to mind, even though that's something else entirely.