change LFS's... you already had ammonia and nitrites. Maybe it has already cycled.
pH can be alleviated by a two part solution. pH and KH will drop over time as they are both used up by the tank.
There are probably better products out there, but I use sea chem marine buffer as a quick fix for this situation. It'll get your pH up to 8.3 pretty easily and get the alk up.. I typically keep my tanks 12dKH and dose if it falls to 10dKH.
You could always shrimp the tank again if you're worried... I'm not going to recommend you to stock just yet, but if it were me, I personally would toss a couple cheap fish in there to test it after buffering lol... like a pair of occellaris or something. Clowns are pretty hardy. You need to pick you up a good 2part calcium/alk solution like B-ionic A&B or kent marine tech CB A&B.