What a difficult decision. I think that if it were me, I would go with the ECHO now and find out if there are any other potential problems that have not yet been detected. Then I would look at spaying once she is a little older and that hole in the chest is better closed. She is such a little sweetie! I am sure whatever you decide will be fine, and she will be well loved! And I agree, everyone on PT will be holding our breath and checking back on the day of the procedure... whichever you decide on!