Hey hon - hugs! It must have been heart-wrenching to let go of Sherpa and Charlie. But they each have done so well in their new homes. Bless you for giving them that chance.

As for now - everything is working, Kyubey is happy, Mama cat is a doll. I'd say foster her a bit longer, but I don't see any problem with you adopting her. Four happy kitties - what more could one ask for?