Welcome to the forum 4nursebee
1. Red Wriggler composting worms are usually used.
2. I would make sure no runoff from a shingled roof gets in the system. Opinions might differ on this but I think it's safer not to let this happen. The pigeons concern me less than the shingles.
3. Yes, but sunlight helps as well.
4. This depends entirely on how you set up the system. For low energy use info you might want to do a search for LEAP - low energy aquaponics. Airlifts are another thing you might search for.
5. Go for full sun - you can always shade using shade cloth but it's tough to move the system into the sun.
6. Depends a lot on your water and how many fish you have as well as the size of your system.
7.
- You could just grow goldfish or Koi.8. Probably not a good idea, I don't know of anyone on BYAP that does this. Here's a thread over on MonsterFishKeepers forum that talks about Koi - http://www.monsterfishkeepers.com/forums/threads/feeding-fish-dog-food.30834/ - Definitely not as good for the water quality and might hurt the fish. A good quality food is important to growing the plants in AP as well so whatever you do, pick something that has enough nutrients for good plant growth.
9.