UPDATE! Wheelie pooper works exactly as advertised!
I emptied out Can #1 after it had sat for 2 years. It had "cooked down" to about half its original volume and it resembled black crumbly potting soil. Very pleasant aroma (smelled like green bean casserole or mushroom gravy or something savory and delicious from Thanksgiving dinner). Not at all unpleasant to deal with. Mixed it into a hot
compost pile.
It should be noted that each "#2" was sprinkled atop with a generous scoop of sawdust. I think all the sawdust helped dry things out and helped develop the crumbly texture.
It also should be noted that I drilled a vent hole under the rim of the can, which I think also helped dry out it all out.
SUCCESS!