You are correct. Sorry. Perhaps I should have stated "true" pope instead of "valid" pope.
No need to be sorry. That's why we're discussing it, attempting to gain some clarity. Yes, Bishop Sanborn has used the word "true", i.e. that Bergoglio is not a "true" pope, but "true" is also a nebulous term and not helpful. There are too many words and distinctions here.
To me the key is that Father Chazal holds that Bergoglio is in some habitual state of lacking authority due to manifest heresy, whereas classic R&R hold that he has authority on a case by case basis. How does someone who habitually lacks licit authority have valid authority? That could only be a state of an authority that's somehow in pure potency ... but authority in pure potency is similar to the sedeprivationist thinking. It almost seems like Father Chazal's valid/licit distinction is a potency/act distinction.
Whenever liceity is used in other contexts, it refers to specific acts. So, for instance, Bergoglio has the authority to make some liturgical changes, but bad liturgical changes would be illicit (due to their being bad). But that's not what Father Chazal holds.