What an adorable HLX! I think you are right - Kira will never accept a cat that only comes to visit once a week - he will only be seen as an intruder. You can either accept that fact and keep them separated during the visit, or try to get him to spend more time with her, although I suspect even if you do, once you go back to the once a week visits she will revert to her hissy self again... 