Thank you for contacting Danco. The diameter is 3.25 inches. Unfortunately, the Disposal Genie will be too large for your sink.
Yes. Sound baffling was a surprising added benefit.
No. the scraper part will not fit in the drain
Thank you for your interest in Danco products. The Danco Disposal Genie is still available in all colors at your local retailer and online.
No, you cannot fill the sink unless you use a stopper with a flat bottom to totally cover the drain, such as this item from Home Depot: http://www.homedepot.com/p/DANCO-5-in-Flat-Suction-Sink-Stopper-in-White-89042/203193999
I purchased black - don't normally shop QVC - due to price and having to wait for my product to arrive.
No. It went in without a problem thru a standard Insinkerator flange.