1) I’ve never heard of using fluorescent lights for heating.
1a) I don’t heat individual enclosures, so I’ll leave this to others
2) they’re very good with customer service. They get back quick. I do think they take weekends off though.
3) I also don’t light enclosures, so I’ll leave this to others
4) I’ve had AP cages in service for at least 10 years I think. I’ve stacked them 4-6 cages high. I’ve never had any warping at all.