The only place I trust 100% to buy fish from online is Dr. Reef. I have 2 new ones arriving tomorrow actually. Great customer service, and extremely nice, healthy fish. Definitely recommend.I read good things about them, but haven't tried them myself. I think I might for my next online order, whenever that may be.
I haven't had trouble with wrasses, at least Halichoeres, with Copper Power. It's really easy to use.
You're doing the right thing by QTing. I know it can be frustrating. For me, getting reasonably healthy livestock is by far the toughest part of the hobby. Sometimes we all lose fish through no fault of our own.