These are different responses that I have heard while reading different post. Trying to figure out what is correct because I am sure many people have heard these.

Trimming yellow and bad leaves- good or bad?
-I’ve heard both ways. 1). Causes stress on plants or 2). Forces effort to new and healthy leaves

How long to add nutrients after a plant has been put into fertilized soil?
-I have heard these different responses. 1) wait 2 weeks 2) wait one month 3) start right away but only use a 1/4 mix.

Pot usage
-1) I have heard to go straight away to a big pot so there are no transplanting issues and 2) upgrade as the plant grows (personally dont know why).

How large of an open air space is needed to for clean fresh air to enter?
I’m not sure if this even matters. 1) Since you want to keep the temp constant and would like to save energy go with a small hole (I have heard even 4-6 in.)
2) A larger opening around 3x3 ft.

Thanks for your opinion.

These are just my opinion im no expert:

Trimming yellow/bad leaves-
I do not remove leaves unless they are falling off on their own.
If they are yellow, make sure its not a nute deficincy.

How long to wait to add nutes-
Depends on how fast your plant is growing. People say if they have strong roots they can take nutes. I have heard some people say wait until the plant has alternating nodes. You definitely don't want to use a full strength feed as soon as you plant a clone or a seedling is popping.

Pot usage-
I would love to just go straight to a 5 gallon pot but I put my clones into a 1 gallon. If the container is too large for the root structure, water can sit and mold, salt buildup can happen if there are nutes in the equation, or the roots might not be able to access the water that is in the container.

How large of an open air space is needed?
This depends on your grow. Theoretically you can have massive airflow from a small area if you have a strong intake fan. as long as you have fresh air being pulled somehow from somewhere you are good. Having your room circulated by a osciallating fan helps too.

hope these helped