Hey all, tried out the dessert and it was quite good. It turns out that that coffee flavor, while not noticeable in the uncooked batter, was definitely present in the finished product, and paired wonderfully with all of that chocolate.
As for the alcohol not setting up as well as the coffee, I'm not sure that I understand why it wouldn't set up. Coffee is basically just water infused with the flavor of the beans, whereas alcohols are probably slightly heavier, since they are a form of sugar. I don't know for certain of course, I think the only way to find out for certain would be to try it.
Oh- and I had another idea for alcohols to add... Kahlua!