I bought 9 citrus trees from Home Depot on sale two or three months ago. I recently moved them inside due to frost. They sit in front of a large 8ft x 4ft south facing window. Now they are of varying health. I'm trying to figure out the best way to grow them. So far, all I've done is water them about once a week.

Questions:

1. What kind of soil should I use? I searched around and it seems like the 5-1-1 mix (pine bark mulch, sphagnum peat moss, perlite + some lime) is a good way to go?

2. What kind of fertilizer should I use? I bought this stuff locally but haven't used any, is it any good?

3. They are in 8x8x6 hexagon plastic containers, should I repot them (remove trees, remove all dirt, prune large roots, put back in 5-1-1 mix, add fertilizer) back into the same containers?

4. Why are the leaves turning yellow on some trees? Do they need fertilizer?

5. Most of the trees are flowering or producing some fruit. a). is this a good time repot? b). is this a normal time to do this or are the trees dying?

Here are pictures and summaries of all the trees. I labeled them T1-T9 so they are easy to reference (ex: T3 is going to die you idiot!)

http://imgur.com/a/AuaOP

Help would be greatly appreciated...