I think Ivan the waiter ends up being Bunny's murderer. Someone else has said Mrs. Gambolini is anagram for M. Mora sibling, which I think is Ivan. Ivan looks like Mabel. I think Ivan is sibling or half-sibling of Mabel, and wants to frame her for murder.

A clue is that apparently episode 7 will feature Mabel's past background. Why would they do that if not to set up that she has a sibling? Also, The actor playing Ivan is already credited to be in episode 8 and 10 as per IMDB, the only others known to be in those episodes are the 3 main casts.

I think Alice is the person that forged the painting. I think that the day before Bunny was murdered she met with the underground art dealer or with Alice. I think Bunny sold the real painting which is why she has a lot of money and can give Ivan a generous tip.

I also think that Cinda Canning and her team are bugging the place, and so they know everything or up to date with the situation. When they saw that Bunny was killed, one of Cinda, but probably Poppy or Cindy sent out the text for them to evacuate the building.