That's a great question and I have an interesting answer for you with some pics; I'll try to find time to type it up later this afternoon.
[Later that afternoon...]
I added one rear remote to my L3200, essentially the same tractor as the current L3301. The Kubota remote kit for the L3200/3800/2501/3301/3901 is not cheap but it's well-made, works well and looks great. So it is the factory valve.
The next two pics were taken just over 24 hours apart, showing that there is very little leakdown. (The mower's weight is extending the top link cylinder.) At the cylinder, over 24 hours there was less than 1/2" extension. Results may vary from valve to valve, depending on time of year, and whether the hydro fluid is cold/hot just before starting the test. But overall I have been super pleased with this valve, and the factory FEL valve too.
The next two pics get to your question about check valves. I installed a remote valve with a "float" option because there are times I'll want the cylinder to move back and forth freely so that, for example, a mower can follow the ground ups and downs. On the other hand there are times I'll want the cylinder to remain exactly where I put it, for example pulling a disc plow or supporting a heavy weight like
ballast or a sprayer.
Cylinders with pilot-operated check valves stay where your valve puts them and do not move. HOWEVER you cannot use a float option with check valves. So my solution was to install a manual shut-off valve in one of the cylinder pressure lines. On occasions where I really want the cylinder locked tight, I can simply close the manual valve. Honestly, I have only used it once since then because the remote valve is so good.
Hope all this helps. Bottom line: I'd try the basic cylinder, no checks, first. Do a weighted 24-hour leak down test and see what you think. You can always upgrade to a pilot-operated check cylinder later if you need.