noobie caretaker taking over someones garden

Hello everyone. I turned to the internet today to find some solid answers to some basic questions. Help! I am a caretaker with very little experience. I have taken over another persons garden who is no longer available. Needless to say we were left with very little tools, equipment or prior knowledge of the little plants themselves. So I am really winging this. Situation: Seven blooming plants from 3 feet to 4.5. First problem. On the advice of an all-knowing guru:
You need to re -veg, too small. light on 22/off 22 about a week should do it and you can start blooming process again. Nope. No vegging after 10 days. Lights back to bloom state. Results: Leaves falling like autumn. What did I do? Fertilized, played music and begged. Two weeks later, coming back to life, new leaves and thank the stars no hermos. So, now the second problem: mites, spray and spray getting under control. We might get a crop out of this yet!

In a shed 12' by 12' 8' deep. Lights ok. Ventilation, only fans.
Another guru suggests to leave the door open a little to let the natural air in.
Results mites again, but surviving.

Please help. I am open to serious like-minds who can give me some sound advise. I do know a little. Of course everyone has their own methods. The basics I think I have.

Peace and HELP!:)

in my experiance mights are a problem you will face. I use a spray once a month i get fr4om my local hydo garden store, works well on mites and seems not to hurt the plants much. just watch what you are using some sprays are more suited to marijuana plants. hope i was of some help

Thanks for the advice. This is what has been used: Floor mite and Azamite. Which is best? What do you reccommend?