Thermoplastic pilot hoses are usually selected for their reduced outside diameter, perfect for confined routing, such as present to the pilot controls.
Hose shops should have access to the components, but, many choose not to, as they are still relatively rare.
So, your gonna need thermoplastic, reduced outside diameter hoses with BSPP ends. Being pilot hoses, they'll typically having a 3k psi operating rating pressure, but the circuits to the pilot valves are usually under a 2k psi. First place I ever saw plastic hoses was on forklifts.
I'd start by checking with local shops, and pricing them out through your yanmar dealer.
Some of the newer "conventional" hoses also have reduced outside diameters compared to older designs. Kinda depends on where they need to route through as to what you replace your leaking hoses with.
And, if you pull them all at once, you had better take lots of pictures, mark them very well, and take extra note of how they orient passing thru the floor and other bulkeads.
Having them all in front of you before teardown allows for changing them one at a time, or at least putting them all back while it's still fresh in your mind.
Caterpillar has such hose in their hose and coupling catalog.
