All of the fish in your selection should get along fine. The only one i"m not sure about is the clown gobie, i've never kept one of those guys but i think they are pretty cool looking. In general, i beleive gobies are quite doscile and I think it would be fine to add him. I like your fish selection. Are you planning to add these to your 40g? Do you have any of these fish in the tank yet?