Congratulations on your adoptees, Frenchie!
I'm not looking for a cat or rabbit to adopt at the moment (I have one of one and two of the other), but since my last two gerbil adoptees died last year, I have a vacancy in my no-cats-allowed "rodent room" again. My local shelter has one gerbil and two rats (the rats aren't together). I know rats can be very responsive and affectionate to their owner, but I've never had one.
I'm not sure you went against your principles. It's wonderful to adopt from a shelter or rescue organization, but you saw those two and fell in love with them.
Peasant (1963-1972) and Fluffy (1970s?-1982- I think of you as 'Ambrose' now)- Your spirits outshone some humans I have known. Be happy forever.