Newbie lighting help

[court_b]

Hi!
This year I bought several new orchids besides Phals and I'm concerned about lighting, heat and humidity for these new orchids. I purchased an indoor greenhouse with the plastic cover. I need to figure out proper lighting for it. I have been reading all the threads in this section and researching lights. It seems that people like the T5 and T8 lighting and that is what I am leaning towards. I have a few questions but let me give you a little bit of info... The greenhouse I purchased is 5ft tall and a little over 2ft wide, it has four levels. My orchids consist of 3 no ID Phals, a hybrid cattleya, dendrobium and oncidium sharry baby. The height range for them is from 3inches to 3ft. I live in Colorado where its super dry and my fiancé likes to keep our house chilly so a light that gives off some heat wouldn't be an issue.
Questions I have:
I know my Cat needs more light then my Phals, so can I arrange to have my Cat closer to the light and my Phals on a lower shelf?
For my oncidium, it's super tall so it will also be on a lower shelf, would it be receiving enough light?
Is a T5 2x2 Hyrdofarm EnviroGro fixture too little light? Would you suggest 4x2? I am afraid that my Cat will get sunburn.

I'm sorry about this long post but any help would be greatly appreciated! I really want to have the knowledge and correct lighting for my orchids now and future ones!
Thanks,
Court