Sanding sealer, usually, is the exact same thing as lacquer----- except that it has stearates added to it that act as a dry lubricant to help you sand it smooth and flat. Keeps the lacquer from "corning" up your sandpaper.
There are folks who will use sanding sealer UNDER a CA finish, but since I'm trained in professional finishing, I live by the vow to never put a super-hard finish (CA) over a relatively soft finish (sealer).
My recommendation is that if you are using CA finish, use the CA as the sanding sealer.
You absolutely CAN use CA as the sealer for lacquer. I spray my pens with a lacquer-like product made specifically for cabinet makers, and I use CA to seal the wood if it's an open-pored wood. Soft (lacquer) over hard (CA) is fine. The converse is not fine!!!