Try putting two human women -- even mother/daughter -- in the same house and they will argue constantly about how things are to be done. Put two guys in the same house and they don't give a rip if anything ever gets done. Same with cats.
Two of the females in our house are mother and daughter and they are just as antagonistic toward each other (the "baby," born in my closet, is now about 3 years old) as if they were total strangers. A male cat, however, usually gets along with any sex, but females don't want other females, yet they don't seem to have the same issues with the boys being here. Puma, our really old female, however, has issues with everyone but me (male/female cats, dogs, whatever). None of the other cats have any issues with the dogs (one Doberman and one Belgian Malenois) but the female cats don't like each other and become especially nasty if there is any argument about who gets to be in my lap.
As far as smell, if you get the male neutered as soon as he's old enough (appx 6 months), then he won't spray on things. All my inside cats are fixed and I snuggle them all and can't detect a difference in coat odor. Cheeks have scent glands, so there is a tiny variation there, but barely noticeable.
My nose, however, is probably not as sensitive as yours and I am not allergic to anything -- I can roll in a bed of stinging nettles and come up unscathed.
