I have only seeded my bucket with 40 adult worms so I can not speak from personal experience yet as I am still growing my farm. I imagine that the bucket can support upwards of 2000 worms, but I think that would be a bit much. The worms will create homeostasis once their populations reach peak levels for their environment, so no worries about over population if you start off slowly.

The worms would appreciate aged food scraps, but it is not really necessary as the food will age in the bin even faster in that moist environment. What makes the worms happiest is if you cut up or shred their food first. The more surface area, the faster food decomposes and the faster the worms can eat it.

If you can supply them with bedding, food, and maintain their environment by harvesting the castings, then there is no such thing as too many worm bins. When it is time to harvest the worm castings is the best time to separate the worms since you will be redoing the whole bin at that time anyways.

Not all gardens are suitable for red worms since they really need decomposing organic matter to eat, on and near the surface of the soil, but if it is a healthy and happy garden then there is probably a good layer of compost and mulch; then they should be fine to be moved into the garden. There are also several really cool designs to build worm towers that are half buried inside the garden. Giving the worms a place to live and eat food scraps, while still letting them go out into the garden to do their thing. I am planning on building one myself once my worms reproduce more since I really like the idea.

I hope that helps with your vermiculture adventure.