The factory Branson rear remotes are decent, and a decent price. I use mine to run my top and tilt. Mine do not have float or detent, which is fine for my use with top and tilt. They hold position well so I don't think they leak as much as some valves.
I have a 3rd rear remote added by the dealer that is mounted on the fender. With the handle mounted pointing forwards it's pretty close to the joystick. I was going to operate a side shift flail with it but never got around to buying one. Instead I bought a grapple. I ran hoses from the 3rd remote to bulkhead fittings on the loader and plug the grapple into those. A joystick operated diverter or 3rd function buttons would be better. I just haven't gotten around to doing it.
I think for your situation I'd start with the Branson remotes and run the top and tilt off them. I would get a summit 3rd function kit for the grapple. It's a decent price for the parts and includes a high quality joystick knob with buttons.
I don't like switching hydraulic hoses all the time when I switch implements, which I do a lot, so I'd spend the extra $$ for a fender mounted two valve unit to operate the flail. You might be able to get a kit from my dealer, Dave's Tractor in Red Bluff CA. Or make one. With dedicated valves you can get some with float if the flail needs that.
You can chain all the valves in series. The lever operated valves will need power beyond ports and the solenoid valves for the 3rd function, don't need power beyond.
