Lots of interesting numbers. Shows that assuming that mylti-axle trailers can simply divide the total TT weight to get the axle weight is almost certainly to give misleading numbers.
The other thing not covered is the idea that the load on each axle is balanced side to side 50/50. Based on actual scale numbers it is not unusual to see many axles off balance by as much as 10% to 20%.
RE what inflation to run. There is hard engineering data to support never running less than the inflation number associated with the max load molded on the tire sidewall. If you want the details you can read HERE
I write a blog on RV tire application and safety. RVTireSafety.com
Also give seminars on tires at RV events across the US. 40 years experience as tire design & quality engineer for major tire mfg. Freelander 23QB on Chevy chassis is my RV