Very glad that the Dryad seems to be feasible for you to use, when you are ready.

Texsolv heddles are plastic and yes they would be easy enough to remove, wash and refit. I haven't used a loom with string heddles but I would imagine they too could be removed, washed and refitted - a bit fiddly to refit I expect, but you don't want your warp picking up dirt, so I can't think of any alternative. (And am now wishing I had made and fitted covers to my looms, cos their heddles must also be quite dusty... )
Will reply to the PM