I can't answer all of your questions, but I'll give some of them a shot. First of all though, congrats on the stock tank, I can't wait to see some pics.
There are a list of edible pond plants in the feeding stickys. I don't know about what to plant them in, or about the lighting. From what a lot of people say, the plants don't last long enough to actually plant them. I know that Marisa keeps some of her plants in a bucket of water and from what I understand doesn't do much else for them. On the other hand, I brought my hyacinth in for the winter and it has since died.
Guppies and rosies are best for live foods. Goldfish are more fatty. Like anything high in protein, it should be a treat and not fed all the time. There is a sticky on breeding guppies as well, if you are interested.
I'd check ebay for the pond plants.
Here's a link to a possible set up with a preformed pond. It might give you some ideas for what to do inside the house.
http://bitz.net/~latazyo/Pics/turtles%20004.jpg