What functionality does the SA-300 provide for on-stage monitoring of vocals and instruments?

I understand that the SA-300's anti-feedback setting can be made quickly and automatically. How does this actually work?

How does the SA-300's anti-feedback system prevent feedback?

Can I get a well-balanced tone from the SA-300 if I use only the upper unit (i.e., without the lower subwoofer unit) as a monitor amp?

The SA-300's speaker grille appears to be made of foam, and I'm worried that it may not protect the speakers during transport. Is there anything else protecting the speakers?

Are there any cautions that I should take when attaching the SA-300's upper unit to the SS-115B speaker stand?