What fish should i get?

i've been running my tank for 4 weeks/1month. at 1 week in i brought 4 snails and 3 emerald . at three weeks in i brought a royal gramma, purple firefish, and da bangaii cardinal. they are doing very well and really love the tank. i just brought 4 more snails today because there still a good amount of hair algae one of the overflows. i notice alot more snails (babies). just wondering if i could get a pair of clowns and either a goby or tang next because this guy that setup my tank gave me 50lbs of his rock and all together i have 100lbs of rock. so im pretty sure it cycled all the way or most of the way atleast. so the guy that helped me setup the tank which he really knows his fish so i might do whatever he tells me and he said get a pair of clowns and either a tang or goby and see how they do. my equipment is:protein skimmer, UV sterilizer, sump, pump, filter socks, 2 overflows, and the tank is filled with RO/DI water. this other guy is telling me that im ready for corals but im pretty sure im not so im going to go with the guy that helped me setup my tank and he checked my water and said i was good. so just want another point of view, should i get the pair of clowns and either a tang or goby? and my cuzins telling me i shouldnt but why would i take advice from him when his tank is all screwed up.lol