Yes. "A small meal" would be "et lite måltid", because it ia not the same for a meal to be light and to be small. A small meal can be heavy, such as scottish porridge or Norwegian cheese, and even a light meal can be abundant, such as a salad. You have to differentiate between "liten" and "lett" to get it.
Yes, “tid” is m/f: https://ordbok.uib.no/perl/ordbok.cgi?OPP=+Tid&bokmaal=+
No idea, why it is different between tid and måltid.
Maybe because måltid is a loan word from German rather than a native compound (https://ordbok.uib.no/perl/ordbok.cgi?OPP=måltid)? (just guessing though, not an expert!)