Sweetie has become a member of the household in a limited way for now.
We have kept her secluded in the master bedroom without putting any other feline noses out of joint. Our cats are free range, coming and going as they please through a cat door, but more often standing with noses pressed to the glass of the slider mentally compelling you to get up from the couch and let them in. So far, Sweetie rarely ventures out of the upstairs and we probably won't let her learn the outdoor property until Spring. She seems content with her domain for now.