We talk to them all the time!
I will tell Dale I think he is the better chipmunk.
My DS told Chip & Dale he wanted to share some nuts with them. He told Eeyore he was his favorite. Told others he loved them. Told Tigger he wanted to bounce with them, things like that.
DH told Minnie to "Dump the big cheese & run away with him". That got a good giggle.
We just generally joke around with them. It is a lot of fun & the characters seem to really enjoy the play. Most really get into it.
My DH told Belle, that Snow White had nothing on her & that she (Belle) was actually the fairest in the land. She loved that.
Face characters stay totally in character & they are a lot of fun to play with.
I asked Peter Pan to take my DS & I to Neverland, so we did not ever have to grow up. Told him my DS would make a great Lost Boy. Peter said he would, as long as I promised to tell he & the Lost Boys stories every night. Wendy piped up that, that was her job. I told them, I had a few more years experience then Wendy & had a few more interesting stories up my sleeves.

They seemed to enjoy that one.