I didn't see either ...
I do not know, I didn't see any pets while there, sorry - will have to call
I don't believe it is pet friendly. The only hotel in the Hilton family that is pet friendly in the area is the Homewood Suites in Grand Rapids. The Residence Inn, Days Inn, Microtel In & Suites, and the Best Western Plus In & Suites in Holland are the pet friendly hotels.
Get an answer from Doubletree Hotel Holland staff and past guests.