I have my mine set up as follows Filter - Duct - Fan - Duct - Light - Duct - Out
Also if the the fan is moving enough air you will have negative pressure and will only need passive intakes where air can be naturally sucked in.
Man this is different but ok. A little lost. They don't seem to be switching to flowering after a awhile of 12/12 and show some defiancys? Think bag size was too big for them but it's OK making it work.