I use Delo 15w-40 with 25 % 15w-50 synthetic mixed in in my Kubotas. However, I make hay which is very dusty so I do much more frequent oil changes. Without that, I would go with the Shell Rotella T 5w-40, which I have used before but decided against it with the frequent oil changes.
I use Wix filters. Carquest, Baxter, Napa, etc. ought to be able to match the correct filter for your tractor. Or, go to the Wix website and they have a filter finder guide. Just enter Kubota and then find your tractor model. Cost is about half of that for a Kubota OEM filter. I would not consider a Fram even if it was free. I use the Napa Gold or equivalent for the tractors, although I think silver is good enough for cars.