The
Disneyland Hotel is wonderful, our favorite hotel in fact. I see you have stayed at the Contemporary, it is somewhat similar to that in that it is highrise hotel. It has very pretty grounds, not as laid out as Port Orleans but very pretty with waterfalls and Koi Ponds. It can get pricey and since you are planning on a busy time of year I would book early if possible. I cannot help you on the suite layout, we have always stayed in a standard size room. I can tell you that the standard rooms are very spacious and can hold 5 people easily. We have been to Disneyland in the winter months including December and February and have swam every trip. The Disneyland Hotel keeps the water very warm and they have a large hot tub so even if the temps are chilly you can still swim. I have never not seen the pools open when we have gone. LucyKate is right though, getting from the pool to your room can be a teeth chattering experience! Disneyland is absolutely beautiful at Christmas, what a nice surprise for your kids. If you can go as much before Christmas as possible that would help with crowds. Disneyland is always crowded on the weekends but with DCA being so close park hopping is a breeze. Also, if you get there as soon as the parks open or even earlier (Main Street opens 30 minutes before the actual park if the official opening is later than 8:00 a.m.) you can get so much done before the crowds arrive.
My favorite dining for sit down restaurants would be:
Goofys Kitchen (our absolute fave), Ariel's Grotto /Cap'n Mickey's (this character restaurant used to be called Ariels, then was changed to Cap'n Mickey's and is undergoing a change to a princess lunch/dinner, no idea what it will be called when you go in December!), Hooke's Pointe and Blue Bayou. Those are all in either Disneyland Resorts or the parks. In Downtown Disney we have always enjoyed Rainforest Cafe, Tortilla Joes and Naples. All of these places are very kid friendly. There are many good counter service options, we love Rancho del Zoccalo, Taste Pilots Grill, Redd Rockets Pizza Port and the French Market. All of those counter service places have huge portions so meals can be shared. There aren't as many choices as WDW but we find the food to be better at DL if a little pricier.
I really love the Birnbaums book for Disneyland, I don't find the Unofficial Guide as helpful for Disneyland as WDW. You will see and enjoy a lot of favorites you are used to at WDW in a more compact, quaint setting. Everything, including DTD is right together, so easy! Some of the rides with the same name are different enough to make you feel like you are getting a whole new experience. Good luck with your plans!