The top link uses ORBF, but for the rest of the connections (ie. coupler to hose, hose to elbow, etc) should I use copper washers between those fittings or just secure the fittings tightly?
Ford 3910, John Deere 420C, Kubota G32XKS, IH 2606, Bad Boy Maverick-60"
I take it you didn't buy the kit with the locks. While you're buying everything piece by piece, throw in some braided hose cover too. The sun will eat up bare rubber hose and look scrappy and cracked after a year or two.
ORB fittings use O-rings to seal. JIC fittings don't use anything--They are a tapered metal to metal seal. NPT fittings use a tapered thread metal to metal seal, but NPT hose ends will have a slight ball and seat seal too. BSP fittings look just like ORB fittings but have a different thread form, count and use a bonded seal (rubber and metal) or a soft copper washer. Don't confuse the two.
If I were you, I'd browse Surplus Center's fittings and hoses and design your layout before buying any parts. Knowing where and what you need will save a lot of cash. Generally, NPT is the cheapest.
Here's my rear remotes and TnT setup. My cylinder and lock ports were BSP. The hose ends are JIC 90 on the cylinder (lock) side. My kit came with all the fittings and hoses. I used flat-face quick couplers and as I remember, I had to buy adapters--JIC to NPT for the couplers I bought separately.