Looking at the post op x-ray the implant placement looks good. Possibly something "broke" during the extraction. This is a common complication. It looks like you were in good hands and the implants appear to be in a good position for a final restoration. The tooth...
From your description, it sounds like the screw holding the abutment and crown to the implant came loose and needed to be retightened. Since it was loose, it may well have had fluid and things seep underneath it that would cause the bad odor.Cotton pellets seem to retain this more than other...