All of the hotels you mention are fine and Jazz gave you a nice differentiation between them. I have stayed at the Castillo 2-3 times and like the rooms, but hate (and I mean hate) the sucky restaurant including and in particular their super lame continental breakfast, which to me seems like management wants to give you motivation to order a "off the menu" breakfast.
I would book the Dunn Inn, if construction is complete, if not have them book you in a quiet area. for the following reasons:
1) The staff is particularly well managed and as responsive as you would expect at a good hotel in the states. The maids, the front desk staff, the restaurant employees, even Boyd(J/K)

provide excellent service.
2) The continental breakfast is actually pretty good and you can augment it with off the menu items
3) The Happy Hour is every day and I believe it if from 4-6 or 7 (2X1)
4) The superior rooms have flat screen TVs.
I have not stayed at the Amistad, but will try it for a few days next trip down.
