Storm has always had dandruff and it seems to be better as long as he gets plenty of moisture in his diet. When I brush him and Sunny I always get a lot of fur that comes out on the brush. I use the furminator and a flea comb. They do seem to shed more during the warmer months.
My other cats don't really liked being brushed so I try to do as much as they'll tolerate. Both Ziggy and Sky really need it though. I can pet Starr and get handfuls of fur sometimes because he's shedding so bad. The pictures of your girls look normal to me so I wouldn't worry too much.:)
