(3 years late "2023" and 1 Health Stroke short!)
Re #3-1
Just my thoughts/suspicion/best guess on the Kubota.... its probably and most likely a SAE J1939 (for whatever Era/Year? of tech) Eg...-11, /21, /31, -01, /71, /75, -81-85, etc, up too /-22. (or some newest SAE or subset derivative.)...