I have a carbon filter before my light and my fan, but I don't know if that makes a difference with the moist air. I have not yet heard of anyone having trouble with their fan because of humidity.

See if you can find the temperature rating for your fan. I can find info about mine on the company's website, and it says the max operating temperature.

Depending on whether your soil has nutes in it already will determine when to use nutes. (If you are using Miracle Grow or other pre-fert soils, just search MG for more info)I have the nutes I'm using in the grow log in my sig. Most say wait until 4 or 5 alternating nodes, and start with 1/4 strength. As for how much and how often, impossible to answer. Some strains require less nutrients and burn easily while others may eat up a lot.