Just drove the car again and did some checking under the hood. I tried to rev the engine at idle to see if the main fan would disengage at high RPM, but when the rev needle hit 4k, the engine started cutting out, as if it hit a protection rev limiter or something. Is this normal? It pulls to redline when driving.

Not sure if the coolant is actually muddy anymore. I have a feeling that the tank itself is stained from before the head gasket was done. When I shined a flashlight into the tank, it seemed clear, almost watery. I could see to the bottom of the tank. From outside though, the tank looks dirty on the inside above the coolant level, and looks as though there is condensation on the upper side walls of it.

Thanks for the advice guys. I'm going to mention all these points you mentioned above to the dealer on Monday or Tuesday, and make sure everything is rectified. I'm going to pull out all the cooling related service invoices that say "customer states.....could not duplicate...performed checked...normal...we don't care....x amount labor hour for diag" hehehe.