I believe saying non-members who are within the Church by desire and imperfect members are two ways of saying the same thing. Again Fenton is very clear in saying that one cannot desire what they already have and that members of the Church according to the "strict" or classical definition are already baptized, profess the faith and submit to legitimate authority.
No, these two positions are completely different. That's why Msgr. Fenton spilled so much ink contrasting the positions and then siding in favor of the "non-members" can be within the Church position.
Imperfect membership is not the same as membership
in voto even. Former camp believe that one actually obtains membership (partially) and it's by virtue of this partial membership (actually achieved, not merely in desire) that they are within the Church and saved. I prefer this explanation to the
in voto school or the position held by Fenton.
But we needn't argue too much about this ... since this dispute is among those who believe that people can be saved by desiring Baptism.
Problem is that you keep putting this distinction out there as a quasi-proof for Baptism of Desire and Salvation by Desire. But it's not really proof, since this particular premise is disputed. You just keep gratuitously saying that non-members can be saved. I on the other hand simply point out that this is an opinion (disputed by many serious approved theologians) and so it doesn't suffice as probative in your logical framework.