per the
dvc host in the gch lobby, there will be receptions held on saturday and sunday from 6-8 pm at the grand villa. we attended last night. giveaways included: dvc backpack, ground breaking commemorative shovel ornament, dvc luggage tags. mickey and minnie in attendance. wine, beer, soft drinks, cheese, fruit.
as for opening day buttons and such, the cast members are wearing commemorative buttons with a depiction of the hotel. they're not for sale but someone mentioned there might be some available at the front desk. there is a limited edition grand opening pin depicting the hotel and chip & dale for sale. it seems to be sold out at most pin locations but we found one by the pin shop near the monorail.