Yes they will be ok. My lfs
has had a rock with about 20 polyps on it for atleast 3 months now under a single t8, the polyps are brown but open up and look ok. I have a few that came as hitchhikers from that store and they colored up with neon green under my halide/led
As far as placement goes in a 30g I wouldn't worry just put them where you want and watch them, if they open up and don't stretch for light then their ok. If they don't open or start stretching then move them.