Given the {-wI'}, is there an unrevealed verb {'opuH}? Or is it yet another member of the family of nouns with {-wI'}: {chamwI', DeghwI', De'wI'}?

I doubt we're supposed to infer the existence of a verb 'opuH. Instead, remember the discussion in TKD on "other complex nouns" (section 3.2.3) where "it is not possible... to know what the individual pieces mean." This goes for the words you listed above: we can hypothesize that those are fixed forms that end with the "one who does" suffix, but we don't know that.

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SuStel
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