Wow that tree house is amazing. Lots of steps, but with all the different living areas, separate kitchen area and that bedroom space at the top, that looks like an adventure in itself.
The thing I like best about our REI tent is I am 6'3" and can stand up in it and still have headroom. It has a mesh top, so if the weather is nice, you can leave the rain fly off and enjoy the fresh mountain air and stars. Now, if it starts raining in the middle of the night and you have to rush to put the rain fly back on, you will get soaked before you are finished...I know.
Our next one will probably be a REI Kingdom 6, very roomy and it does have two rooms, for us, more room for the dogs.
Check it out. Plenty of room for you and for T and friends:
https://www.rei.com/product/894016/rei-co-op-kingdom-6-tent