Jeff, thank you for replying.
Without an associated MTL file, it is very, very difficult to import, edit then export a 'busy' OBJ. Did you get an MTL ? My 2016 TC ProP offers no obvious options that might enable its I/O.
I've been gifted several OBJs whose MTLs make ~1000 external texture calls. I dare not edit nor adapt these near-photo-real architectural models with TC because it is impracticable to reconstruct their MTLs in post-work.
FWIW, TC 2016 does not support FBX, but I have analogous problems in other programs when an FBX has been exported without texture calls. Aside from FBX version 'tree' issues (v6 'trad' vs v7.1~7.4 'trad', 'mutant' and 'splat') even when a folder of texture files is supplied as solid colours or maps, matching 50~~90+ parts to their textures is non-trivial...