Not a good mix you have there for compatibility. Puffers will destroy inverts including that Brittle Star and Dottybacks are terrible community fish as a whole (well known for being bullies) and putting 2 of them in a 29 gallon would make your odds of success pretty low.
I would do either of the following:
1 Clownfish (Ocellaris or Percula variety only)
1 Valentini Puffer
1 Royal Gramma Basslet (similar look to a Royal Dottyback but you have much higher odds of success with getting them to coexist)
Royal Gramma Basslet
Small Goby or Blenny