It appears that you're off to a good start! I'm not sure I would have added your first coral yet, but if your water parameters had been good and stable for several days prior to adding it, it certainly wasn't the worst thing you could have done. Mushrooms will do just fine with practical reef lighting (as in T5 HO or MH are not required) and low to moderate flow. If you have 2 x 96w PC lighting, it would probably do just fine somewhere in the mid-section of the tank, and possibly be ok near the bottom (not sure on the height of your tank). It may eat small mysis shrimp or a tiny bit of Cyclop-eeze, if you want to try and target feed it. I've seen some mushrooms accept such foods, while others weren't the least bit interested. FWIW, I don't target feed any of our mushrooms, and rarely target feed our other corals. I pretty much operate under the premise that fish poo makes excellent coral food.
It can be surprising how much salt spray / salt creep can form on an aquarium lid, aquarium trim, the protective lense on a light fixture, etc. just from a slight rippling of the water's surface, let alone any splashing. Definitely keep an eye on it, as any that builds up on any surface between your lighting and the water will greatly reduce the amount of light making it to the water's surface.
Perhaps it's just become my preference, but I think you'll want to add more flow to the tank. When I first started, I thought "enough" flow was actually enough, but over time I've grown to prefer having much more than what many would call "enough." Rest assured, you certainly don't want to be blowing your mushrooms and zoas off the rocks, but detritus is very good at finding places to settle and build up if there's not enough flow to keep it suspended for whatever form of mechanical filtration there is to remove it from the water.
