Most Kubotas are open circuit systems until they get large and more industrial/commercial type tractors. That means that these open circuit systems will have a power beyond sleeve in most additional valves (FEL, rear remote,…). The exceptions would be the backhoe valve and the 3rd function (grapple) valves. Those are designed to not require the power beyond adapter sleeve but all other valves should have the sleeve. I don’t the log splitter valve needs the PB sleeve if it is piped correctly to be independent of the three point hitch but if you intend to use the three point hitch with the splitter valve installed then it does need the PB sleeve.
In short, yes you have a PB sleeve in your FEL valve. It is easy to identify as the T port with an extra adapter screwed into it.
As far as hydraulics go they are easy to do yourself as long as you understand how to connect them. The hardest part is usually getting the correct adapter fittings between valves and hoses and getting the hoses routed well. So you can do this if you want. Just use
@TheOldHokie to verify the connection points and hose routes between valves (not the physical places the hoses go).
Since you are working on a cabbed tractor, the hydraulic block may be hidden away somewhere that is difficult to access easily. If that is the case, then you may need to add a remote access point for the splitter connection instead of just installing the disconnects into the tractor.
The block on your tractor should be covered in the tractor manual, but the FEL will have its own separate manual.