Thanks for your reply.
I have spent time with them and have not had any problems with allergy. I also lived in a house with a cat for 6months about 6yrs ago so I presume any allergy would have shown up but thanks for the question I hadn't even thought about allergy!
Yes just thinking of one because I don't know what to expect and also the cost of vaccinations, food etc
By fixed I guess that means spayed/neutered - yes they are now!
I don't think they are particularly close but I've never been with them full time just visiting so I can't be sure - I would hate to upset them by separating them,