Don't worry about the rats bonding to eachother and not to your brother. Believe me, I have nine rats and each one of them has a special bond with me. Back when I only had four or so, I still had close bonds, too.
Always have rats in same-sex pairs! They're pack animals... they thrive much better with another furry friend of their own species.

And I find that homemade mixes supplimented with fresh fruits/veggies and mineral blocks are the best. Just google up "homemade rat mix" and you should get plenty of examples.

And about the color of rats. I have various colors... anything from blue to agouti(brown) to almost pure white. I don't see a different in their personality when it comes to color. My agouti hooded is super sweet & squishy while my other agouti is shy and timid. Same color, different attitudes. Remember, rats are all the same breed... just different colors.

And I previously had a PEW(albino), and he didn't have any problems. He wasn't nippy, but they do tend to have poorer eyesight than others. As long as you make sure not to scare or sneak up on a PEW, its usually not a problem. Plus, I've seen plenty of BEW(black eyed whites) around... so thats a possibility, also.

Hope I was of some help. =]