Love the look of your plan. I give another vote for HRH. I stayed there at the very end of November and loved it. Stayed at Royal Pacific a couple of years before that, but much prefer HRH. The staff are fantastic and the whole place is just fun. Of some of those negative reviews (just quietly) if you're old and grumpy enough to be bothered by the music in the halls and elevators, well...you picked the wrong hotel
also, the beds are super comfortable and they have great quality sheets (something Disney could learn from in their 'deluxe' hotels...)
The walk to Studios is so great - it really is just five minutes to the gate (go down to the pool, veer left, there's a gate, follow the path to a T intersection, turn right and follow the river around).
If you want food ideas, I ate at both the Velvet Lounge and The Kitchen at HRH for dinner and I'd definitely recommend them. Also the new Italian place on Citywalk (sorry, can't recall the name) blew my mind (and my tastebuds haha).
I don't know about having to book HRH early, but, depending on how many people you're travelling with, you may want to buy at least one annual pass and book the discounted rates. I bought a package and then upgraded my four day pass to an annual, and it only cost me about $85 more. I more than made that back in food and merch discounts, and will be using it again for this year (both for entry and booking discounted rooms).
You should feel lucky to get into Boardwalk. It was my first choice when renting DVC points, but I couldn't get it, even at the 11 month mark. Very happy with Beach Club, though (so much I'm going back in November). If you're there for Christmas decorations, be sure to walk around and see the other resorts. Also, keep in mind it might be quicker to jump on a bus for Beach Club and walk to Boardwalk rather than wait for your resort's bus. I missed the BC bus by seconds one night at DTD, and a huge crowd of Brazilian cheerleaders had just broken into Christmas carols. I was desperate to get outta the place, so jumped on the Boardwalk bus. Everyone complains about transport from DTD, but I was at the resort in 11 minutes, and then just a walk around the lake to home.