The CMA, CMSF1 and CMSF2 games form one family in terms of terrain modeling and the rest of the games are another. And there are much bigger differences than some buildings or Flavor Objects. The transition between these families is, in my opinion, impossible. In addition, CMSF2 is much richer in terrain elements than CMA, so the transition from CMA -> CMSF2 is trivial but the other way is probably possible after a solid reworking of the original map. We can rather forget about other conversions eg. CMBS -> CMSF2, CMFB -> CMA...
To convert maps you need a hex editor, eg Hexedit. After opening the map file in it, replace the first position in the second line according to the rules:
00 CMSF and CMSF2
02 CMA
04 CMBN
06 CMFI
08 CMRT
0A CMBS
0C CMFB
If there are problems with the map conversion, remove Flavor Objects, then buildings and bridges.
But let me remind you - all this works quite well within one family of games.