1. Chaeto doesn't produce pods, they usually live/hitchhike in it.
2. Some crush coral leak po4 so too much is probably not a good idea.
3. Yes they can be transported through the pump. Not all will make it through alive.
4. Siphoning will remove some pods but the ones that remain will reproduce.
41/2.Siphoning is not necessary but can be done once in a while.
5. Pods need food, when there is a constant supply they reproduce more. Any kind of fish food will suffice enough to be eaten in an hour or so.
6. IDK.....