Yes, you can use it, but consider some things:

They dont only give little presion, so they are only valid if there is no ducting. If they are free, and ducting need, you can put some in a stack.

They dont flow large volumes, in general, and sure for silent ones. 12cm fans can easy double the air volume that tipycal 8cm fan can move. 8cm fans works fine for venting into the cabinet, but at least 9cm fans are required for extraction, or you will need a bunch of 8vm ones.

They will work fine for the CFLs and the 150w HPS, but you will need a lot to use them with the 400w HPS.

The best way to put them is with regulable transformers to 12V DC, so you can easily regulate voltage, RPMs and noise (clean them often if you want to heep them silent, and run them at 9v if you can).