-
SunRace has an ok 1x specific square taper crankset, I think it's called FCM800. I've seen it on quite some builds and used it myself with a SunRace CRMS chainring. Tad ugly, tad heavy, but cheap.
Otherwise just buy any old 110 BCD LX/DX/XT/whatever you can find. After '93-94 they switched to 94 BCD, watch out as the chainring options are going to be extremely limited (mostly Stridsland only).
3x7 to 1x7 conversion. On my MF Pathfinder I've got an SR chainset with rivetted small ring. Should I just get an old Deore something square taper replacement and fit an nr chainring or is there some decent modern replacement? Looking at a cheap conversion, hence sticking with 7 speed.