Hi Bill,
[welcome] to FOG,
Kapex is a system and quickly becomes a way of life. Given that you are buying a Kapex for a specific job on site, then for sure you will need a stand. One way to go is the MFT/Kapex but that is not so handy when you need to move from room to room. From what you shared about the job a UG stand with extensions would be your best choice to support the Kapex.
You will need top-quality dust extraction. My suggestion is the CT26 or CT36. Those use the same top with the motor and blower, as does the CT48, so if you start with say the CT26 now later you could purchase just the bottom of a CT48 for added capacity.
Kapex needs the shortest possible 36mmAS (anti-static) hose. What has worked well for me since the Kapex arrived in the USA is to buy a 36mm x 7mAS hose and two extra sets of fittings. Then I cut the 7m hose into 3 equal lengths. Those 2+m lengths are enough to connect a Kapex to a CT26 or CT36 without kinks.
If you decide to buy a Tradesman Clean-Up set, make a deal with your dealer to up-grade to the 36mm x 7mAS hose. In that case only buy one set of connectors and cut just over 2m from the long hose for the Kapex. This will leave you a most useful almost 5m of hose for cleaning. While you can clean with non-AS hose, cleaning is even better with AS hose. You really benefit from AS hose for extraction on all Festools.