Can Tablets deal with USB Sound Cards? I've found this thing on eBay. It converts the USB to a microphone input and a jack-speaker output. I'm just curious, if my tablet is compatible with it as the description doesn't explicitly mentions it.

My device is rooted if that makes any difference.
Extremely doubtful, to the point where I'm confident saying no, it wouldn't work.  It would require either the OS dev team having included Linux drivers that would work with the USB device, or the USB device manufacturer having released Android-compatible drivers that you could install on your tablet yourself.