If you get the males when fairly young, you should be fine as far as the fighting goes.

Dog food is for dogs, not rats. You can use it but you really should suppliment it with a grain mix. They also need max 16-18% protein, so that usually means a senior dog food. The hog feed recommended in the ASF forum is cheaper than dog food and would probably work out better for them than a diet of straight dog food.

I am going to go against the grain here and say that in no way is 10 gallons adequate space for one rat much less 2 females and a male. I know some breeders on here will put feeders in as small a space as possible to save room, but rats are just too large as adults. I have several adult males that are 800+ grams and there is barely enough room for them to turn around in a 10gallon. I keep rats as pets and not as feeders, so feel free to disregard my opinion on this.

Good luck with your colony!