Well, the plant should be ok going from outside to inside, thats what some people do to flower them.

The posts need to be 3 - 5 gallons, then you neeed never worry about root probs, just make sure theres plenty of drainage.

Lights depends on how many plants you want to grow.

1000 would be too much, so we can count that out.

I'd say anything from two 250 watters, a 400 watt, or even maybe one 600 watt HPS.

I'd say if you can get MH and HPS, so you got the MH for veg with its blue spectrum, and the HPS for flower with its red spectrum.

If you cant get both then no need to worry, id still go with the HPS for veg and flower.