Botanicare makes a low profile tray
https://www.sunlightsupply.com/shop/product/botanicare-pallet-rack-tray-4-ft-x-8-ft?categoryId=grow-systems-trays-reservoirs
Every should be cool just watch the light levels when moisture is applied to the plant. T5's are perfect for starting seeds and are very under estimated.
No matter what measures you take as long as there is a major mite problem next door it's just a matter of time before their in you room. His problem needs to be cured ASAP?
Auto's have no control of the plant the last thing you need is to invest all the time and money into something you can't control. I would ditch the auto's.
Topping is important to get a big yield. The more top buds means more weight in the long run. Topping plants early gives the plant more opportunity to produce more tops before flowering.
Check prices on Amazon for cheaper prices. Never used the Coco bloom. I'm currently using Emerald Harvest which is cheap and very effective. Made by someone who worked with Advance.