Okay, Exiled Force requires that you tribute it while face-up in order to activate its effect. Rescue Cat requires that you only send it to the graveyard while face-up to activate it. King Tiger's effect allows it to override Exiled Force's priority and destroy it when it's normal/special summoned, thus preventing you from tributing it and activating its effect.

Now, my question: is this also true for Rescue Cat? Or, does the fact that you only need to send Rescue Cat to the graveyard instead of tributing it give you priority over King Tiger's effect, thus allowing you to ditch it as soon as you summon it and activate its effect while KTW's on the field?

The ruling regarding "Exiled Force" will apply to "Rescue Cat" also. Both are Tributed/sent to the Graveyard as a cost of activation and if "King Tiger Wanghu" can override one then it will override all of them.