You'll need a lot of rockwork, and to watch for aggression, remembering that the final tank dynamic won't be determined until they all hit adulthood. Could work out, though. And, yeah, you can pretty much consider the neon and the clown goby to be one fish, both in terms of bioload and of space demands.
Frankly, Dr Reef has gone way downhill, from what I've been hearing. Good return/replacement policy, but bad shipping practices and insufficient quarantine- people have been getting sick fish from him. There's a couple threads discussing it here:
https://humble.fish/community/index.php?forums/quarantined-livestock-vendor-information.140/
I love FisHotel for fully QTed fish, though it is a bit tricky to get stuff from him. If you can be around on the forum when he gets a semi-custom order in (he'll give a list of what he can order from X place, people put in requests, then he orders all that), you have a solid chance, or you can stalk the website for whatever people don't buy off those orders.
Though do remember that if you go full QT (which is generally a good choice), you need to QT nearly everything wet. Non-fish need a fallow period, 10+ feet away from your display, before going in with fish.