QUESTIONS FOR THE EXPERTS - WHY WOULD THESE CLONETANKS SHOW CORRECTLY IN MAPVIEW & MCDEDIT BUT BE MISSING FROM THE REAL GAME?
The map files are corrupted - this is something that could happen with maps created with old MapView versions. What is happening is that the .map files have data assigned to them that isn't displayed or written over by MapView, but you see the bad data displayed on OpenXCom.
This can be shown on the below pic where I've replaced the PUFOL83 with the vanilla URBAN tileset in the ruleset. The black tiles are replaced instead with entries from URBAN.
To fix this, my advice would be to create new map files from zero using the newer versions of MapView, which means you'll have to recreate all of the maps again (I've seen the bug on several other pyramid maps), but since they're already designed, that will speed up the process, and you'll never have to deal with this kind of bugs again.
In alternative, you can always trying manually editing the files with an hex editor, which is a challenge of its own, and you'll never be 100% sure if you eliminated all the bugs.