Bit late to the thread as it seems you already have your mind set, but a few things worth mentioning.
1. No need to detach the backhoe. Just unhook the hoses. The concern then becomes the boom drifting down. Double check your manual. I could be wrong, but I have yet to see a backhoe that didnt have a place to chain the boom up. You are actually supposed to do that when transporting or driving down the road. On the main boom, about mid way up should either be chain hooks or keyhole looking slots that a chain will grab into. The same should be on the ends of the outriggers. Raise boom and outriggers up all the way and chain as short as you can. Then lower the boom (preferably with gravity and tractor off) to take the slack out of the chains. If you dont do this, the boom can drift and you might have a hard time recoupling the backhoe if those couplers arent a connect-under-pressure style.
2. What type of plow are you going to use? There are basically two types, rigid SSQA types, and converted truck plows that have a chain lift. For gravel or rolling drives, the chain type is the preference. Because without a chain to allow ONLY the plow to float, you are either going to be constantly adjusting, or putting the whole loader in float. Which dont work real well as the whole tractor tries to drive up over the loader, and you loose steering. Have you ever tried to Float your loader bucket going forward? Now imagine that happening when plowing.
3. A pair of SA cylinders like a truck plow normally has is preferable. A few reasons. 1. You will have equal angling speed. A single DA cylinder will be fast one way, slow the other. 2. Equal angle force. Same as before. A DA cylinder will be weaker one direction and stronger the other. 3. The ability to use a crossover relief. You CANNOT use a crossover with a single DA cylinder. Well, you can....but it aint gonna do squat. If you catch something with the edge (side) of the plow, and the cylinder isnt already fully retracted, you put a heck of a pressure spike in the hoses and cylinder. Hit something hard enough and you pop a hose. Think about a floor jack. You have a handle that is pumping a little rod that builds pressure and raises the jack. Well the plow is the handle and the cylinder is the little pumping rod. You have alot of tractor/weight, and with some speed and leverage, its easy to pop a hose. Which would be a big concern of mine using the rear remotes....just depending on where you route the hoses. (Right beside you?) The crossover relief protects against this by dumping oil from one cylinder to the other once a certain pressure is exceeded. But they only work with two cylinders of equal volume. A Single DA cylinder has differing volumes.
4. Have you considered a diverter or third function? I did a diverter setup on mine and a joystick for the loader with a button. I had just a tad over $300 for everything but doing over again, it would have been cheaper because I would not have used the expensive flat face 1/2" couplers. I would have just used 3/8 or 1/4" couplers similar to what snowplows already have. All I run is a grapple and a plow, no need for massive couplers.
There are links in my signature regarding a diverter install, as well as a truck plow conversion to use on a tractor. Truck plows are a dime a dozed compared to SSQA plows