You are correct, HST filter is on the left side and hydraulic suction filter is on the right.
You may already know, but just in case. Kubota has their parts fiche available online and is very helpful for looking up stuff like this, seeing how things go together, or looking up optional features. Also for comparing models and parts it has proven handy.
Yes, Kubota has a parts section on their website, or Messicks webpage is great as well.
Strap (steel band or seat belt style) or channel lock wrenches work well for most filters, I've bought those socket type ones but never use them.