Which one is Lois? And which one is Ma Kent?
Here's my reading of it, from left to right:
Pa Kent (Looks like the Pa Kent from Birthright, but I could be wrong.)
Ma Kent (Extrapolating from the above being Pa, I figured this was Ma. But on 2nd inspection, she looks too young and her hair too long. Plus she's got the 'S'. Now I'm thinking she's a previously unknown Kryptonian.)
Supergirl (99.9 % certain about this one.)
Superman
Maggie Sawyer (Still looks to me like an Earthwoman. I'm guessing that Kryptonians don't smoke. I seem to recall that Maggie does, but I'm not sure.)
Lois Lane (The only brunette in the bunch. I'll go with 90% certainty here)
Upon further inspection, it seems that the two standing next to Supergirl are her parents, as they match the couple shown on the page previous to the one we're discussing (in Action Comics #850), where Supergirl exclaims, "Dad! Mom! You're alive!". I agree with you that the other women looks like Lois and, as you said, possibly Maggie Sawyer.