It's been the better part of a week now, and Benjamin's reinstated naps are going amazingly! I hesitate to rejoice so soon, but I have learned so much in this area even in these few days that I wanted to write it all down.
First, having Ben up "late" isn't terrible at all. I rationally explained to the older two that because Benjamin was napping, he was going to go to bed a little later than they. To my surprise, they gave me no troubles on this at all. (If they had, I would have told them that they could stay up late if they were willing to take a nap, which they never would have agreed to.) And even sneaking Benjamin into bed (they all share a room) is fine, as they are dead asleep after that hour has passed.
Second, it hasn't cut into James' and my time at all. We have slipped into a rhythm of my putting Juliette to sleep and then tidying up while James plays with Benjamin. Ben is relishing the one-on-one time with Dad.
Third, Benjamin is infinitely more pleasant to be around. The incessant whining has pretty much disappeared. The crying over small things is completely gone. When the boys get home from school, Benjamin is fresh up from his nap and there is no fighting or teasing on Ben's part. The famed "witching hour" (4pm-5pm) is a pleasant and (dare I say it) almost peaceful time as I get dinner on the table.
Fourth, enabling the nap, rather than forcing it, is starting to work. The trick is not letting it get too late. Ben is yawning, tired, and ready to sleep by 12:30pm, and I've discovered letting it lapse much later than that results in an over-tired child who resists sleep (getting back into that overtired bad behaviour.) The weather is starting to improve, which means we've been able to get outside and get some fresh air to help wear him out. I also let him lie in his bed with a couple of books for the first 15 minutes or so, to wind down in a darkened and quiet atmosphere.
Lastly, the discipline. This is where I've really grown as a parent over the last few days. The article I read on getting your 3 year old who doesn't want to nap to go to sleep is to firmly explain the consequence of not taking a nap, and implement when necessary. The consequence I've told Ben is that Daddy will not play with him after the boys go to bed, if he doesn't nap. Today I had to state and restate this five or six times: "If your feet touch the floor, there will be no playing with dad." I gave up saying "if you get out of bed." The statement "feet touch the floor" was much more specific and clear for Ben.
For me, I find that I usually try and ease the path so that what I want happens, or else I snap when things are completely awry, showing more than a little displeasure at disobedience. Today I felt myself empowered as I stood and firmly asserted my position as parent. Felt like a good step up.