I was wondering about the seat switch and spring changes as your pic showed that the other welded on pieces for the switch and the springs were not there. I still don't see these changes in the parts manuals as yet.
I replaced the seat on my Tiger Cub with a similar one to yours, but no switch installed and no "Scag" name on the seat. This seat is much heavier that the stock seat was and compresses the springs holding down the seat switch with no one on the seat. Evidently Scag has dealt with this problem by removing the springs and seat switch from the support and putting the switch in the seat itself.
I will ask the manufacturer of the seat if a switch is available to be installed into the seat and if so I will make the change.
As for the caster touching the deck wheel, check if there are additional bolt holes that you can move the wheel bracket into to get more clearance from the R/H caster wheel.
I did notice in your pics that the electronic control module connector had dirt and dust in it. I clean the electrical connectors on my machine periodically with HP air. Dust in these connectors increases the possibility of electrical continuity problems. Years ago I tried conductive electrical connector grease on these type of connectors, but it made the dust and dirt accumulation much worse and difficult to cleanout, so I just inspect, clean and reconnect them.
If you plan to readjust the deck level, let me know and I will give you the basics of this adjustment procedure as the manual is somewhat confusing to follow making the process much more difficult.
I gotta hookup my trailer and get mowing, another hot one today, but I gotta do what I gotta do!!!!:laughing::biggrin::smile: