Will this work?

[RandomGemini]

I have a 7 gallon minibow aquarium just sitting in my garage taking up space with a fluorescent retrofit kit that I installed with the idea of keeping corals. There's a 50/50 compact fluorescent in there now. 28W but I can easily order in a plant bulb from the supplier. I have concerns that my orchids will not get enough light on my window sill this winter because, in December, we'll have day light from about 9 am until 3 pm. So I'm thinking I'm gonna have to supplement light somehow and I want them to stay warmer during the day anyway.

I was considering getting some inexpensive aquarium gravel or using some cheap bark mix as a substrate and setting up this aquarium with my three mini phals in their pots in this tank, with the lights from this tank on a timer, so I can control how much light they get, without having to think about it too much.

The questions I have are:

Will it be too much light on my mini phals in a tank of that size?

This aquarium has a couple of openings in the back of the hood, if I leave those open, do I need to worry about installing a fan to keep the air moving? (I can probably retrofit a CPU fan to do this job if I have to.) I would continue to water and fertilize as I do now.

What am I not thinking of? I've never set up a terrarium before.

Thanks much!