just aquired part of a system

Welcome to the forum.

The AV505 is a nice 5 channel amp. 80 wpc with power steering. Very nice amp for driving a small HT.

The TFM 15cb are nice two channel amps. 100 wpc and you can bridge them to one channel for 280 watts of power. I have two of these in my HT. One bridged into the center and the other going into my rear speakers.

Cerwin Vegas are not the best speakers. I would stay away from them. I would need to know your budget and room size to recommend a set of speakers. Also are you going to be using as a Home Theater or 2 channel?

I'm not sure if you can use the preamp on the receiver to use to control the power amps or not, but I believe I would find a way to hook these items up to some cheap speakers just to see if they work or not before dumping a wad on speakers. IMO.

A lot of members here seem to like the Polk Audio line of speakers. I have the MB Quart Alexxa S-one that I really enjoy. If I were to look again at speakers I would research the Polk that you can bi-wire or bi-amp. Can't do that on the MB Quart. Good luck