First grow, need some advice.

I currently am in my first grow. I have four plants coming up, three under two "grow" lights from Wal-Mart (Lights that claim to be plant growing specific) and one under it's own bulb. The plant under it's own bulb is growing much faster than the other three (which I attribute to the different lighting it has) while the other three grow nice and steady but at a slower rate.
The three under the two bar lights have started to get yellow spots on the leaves at the bottom and the shoots seem to have a little red in them, while the bigger plant has more of a cancerous (more like blotching than spotting) spotting also on the lower leaves. In this set up I also have a small fan at the top of the closet that blows 24/7. I had them on a 24 hour light cycle when they where small, but when I transferred them to their three gallon buckets, I put them on a 12/12 lighting system.
I have been growing them now for about three months and although they get bigger they do seem to be a bit stunted.

So my questions are as follows...

-How to cure the red shoots and yellow spotting
-How to cure the blotching on the leaves
-Should I be running the fan 24/7
-Should I be on 12/12 lighting
-How do I know it's the right time to flower them and how long should that process be
-How long should they grow before it is time to flower, after almost three months they are about a foot each, should they be bigger at this point
-How much yield can I expect per plant

I appreciate any and all help I can get, I didn't even expect to get this far, but now that they are about a foot tall I want to see them come to flowering.

Thanks!

the light you gpt suck and are no good your better off with compact flourecents from wallmart if you cant get Mh/or HPS lights . Did you feed the plants nutes sound like you might of over fed the reson yout plants are not growing is caus eyou need more light your gonna get some wimpy buds with the light you have.you are ready for 12/12 you stay the time there depends on strain you will know when buds full grown looks readdy to smoke usually 60-70 days of 12/12 hope this helps.