Series of Questions mainly about Repairing Soil

My Dad got 6 clones and they were starting to get yellow tips on the leaves at like 2 feet tall back in May so I paniced and got Xpert Synthetic Fertilizer. We used all that and they got to about 4 feet tall all fine but we didn't want to continue using it as I was researching all the aroma and taste issues that my panicky scenario could of done. I heard this can do weird things to the soil. I bought the fox farm trio Tiger Bloom Big Bloom and Grow big and the plants are now about 4 feet to 5 1/2 feet tall and a couple weeks into early flowering.

1. My question is now that we used synthetic fertilizer what do I need to do to repair the soil to a living ecosystem again?
2. Also how do I calculate how many gallons of diluted fertizilzer to use for these 4 feet to almost 6 feet Marijuana plants?
3. Another thing they have 3 feet radius of space is that enough space or am I slowing them down and overcrowding?
4. I used 2 gallons at 1 tbsp/gallon of Tiger Bloom on each plant cause it seemed like enough to get fertilizer to all the roots on each and that's what my roommate thought we should do.
5. How helpful would bonemeal or adding something to make the pH 6.0-6.5 as I heard on weed schooling youtube channel.
6. Also should I be using lime/phosphoric acid and measuing the soil pH to make sure it is a good pH. Is cultivating the soil to make the top one inch aerated good idea?
7. We forgot to trim the branches and two of them look like Mother Plants for cloning and am afraid it will get to humid inside should we trim them to make them look like AAA bud producing plants or will that shock them too much during flowering stage?
8. When we go to harvest the bud should I microscope every bud and only cut the ones that I see milky white or white trichromes on and leave all bud that isn't white?
9. How helpful is adding a layer of steer or chicken manure to the top of the soil? Is Compost Tea really helpful even this late in the stage should I buy that as well?
10. Again I used synthetic fertilzier (Xpert grow its called) so what do I need to do to repair the soil or possibly flush the plant and
11. Again how much Fox Farm gallons at the recommended tbsp should I pour per 4-6foot plant with a 3 foot soil radius in the garden bed.
12. How helpful is getting the soil tested?
13. Some of the branches are dieing and there is a brown spot at the base is that dehydration because sometimes the soil is dry for 24 hours before we water again because we don't want the plants to be constantly wet on the roots. Or is the brown on the branch possibly mold or stem rot or something? There were three or so leaves that had a tiny drop of powdery mildew on them so we used Neem Oil since then. Then branches with brown on them snap off with the lightest of touching when we are looking inside the plants to inspect I think it's dehydration but was hoping for some conclusive answers.
14. Bug are eating the leaves and leaving holes what organic solution will repel the bugs
Should we use Serenade to prevent the stems from snapping off if it is possibly mold?
15. One branch is dieing should I cut it off with scissors and spray hydrogen peroxide on the wound to sanitize it?
16. If there is mold on the branches should I pour hydrogen peroxide one part to ten parts 3% solution in the soil to kill the spores?
17. Next year we want to start with clones again will getting a 300 watt light be enough light until they are a couple feet tall and it is warm enough but mainly big enough to be outside? We will have a big fan and an open window nearby as well in either the living room or my closet.
How important is it it to santiize with rubbing alcohol all your garden tools because I just learned this since I might have mold in the garden do I need to wash my clothes everytime I'm done each day?

 

They are about the same size as a nickle all over. My dad had been building the soil before I used the expert plant food when they were dieing.