Not sure I looked and listened while it was on and I don’t think there is a cooling fan but there is a lot of ventilation. And it runs a 1500 watt surround very well.
#3 Does the remote operate power on/off? Or is this a typical issue with all Pyle receivers?
No, the remote takes it out of standby mode. Must use the power button on the unit to turn off power completely.
#4 How is the sound quality using Polk bookshelf speakers and a powered woofer?
I had a Sony DNR that died so I replaced it with this and I could not tell the difference....same speakers same room
#5 Can you use the subwoofer preouts (l and r) to send the signal to a power amp via rca cables? i want to have a power amp to power my passive subwoofer
It has and output for passive sub first left of the speakers and two for powered sub. No need for preamp.
In the unit itself, no, but you can connect a blue-ray or CD player through HDMI ports, I suppose. There are 3 HDMI ports, an optical port, and one coaxial port.