This is a really great start! My entire collection is grown indoors and 80% of them live in a modified Rudsta Wide and Tall. There will be a lot of trial and error in the beginning.
As stated you will need fans to keep air moving. Also for lighting, I would suggest studying this article closely.
Target PPFD for Orchids and Tropical Plants
– High Desert Orchids
I believe you are giving these plants more light than they need with the distance they are at. They may not be burning, but it could be that over a long period the cells will accumulate a lot of damage and can reduce the lifetime of some of the plant structures. I have yet to see scientific data on this though.
I would recommend weather stripping the side panels and a bit of the front panel. You don't want it to be 100% sealed, and you will need to calibrate how sealed it is based on your household conditions. This will be a bit of guess and check, but I find the front door seam a good spot to play with to get the desired humidity.
I would also recommend buying custom acrylic shelves with holes to replace the glass. This will increase airflow between the levels, and help heat from accumulating at the top of the cabinet. With two thermometers, you will see there is a large difference in temperature between the top and bottom. They can be expensive though, so don't stress about getting them right away.
I also run an air filter 24/7. It keeps dust down, and maybe it helps reduce fungal pressure by filtering out spores. I don't have anything scientific to support this though.
I use a smartplug to time the lights and to time the fans. My fans are 1 minute on 1 minute off repeating during lights on. 2 minutes on 1 minute off at night as humidity gets really high in my cabinet at night (80%).
I am attaching some photos of my setup and conditions. The large humidity drops are when I open the cabinet to take stuff out or look at it. You can see the humidity quickly goes back to baseline.