Decided to try the Windows 10 upgrade, and I can confirm that Test of Time (with TOTPP) works fine on it (played a couple of dozen turns). No compatibility mode needed, just take the ordinary installation instructions into account (e.g. don't forget to install codecs, use a 64-bit compatibility patch on 64-bit versions, etc.). This means that MGE will almost certainly work fine as well, since it's a slightly older version of the same engine, though I haven't tried it.