If you are going Spring Break this year, you will want to start trying to make ADRs now, since as mentioned by PP all guests can make them beginning at 180 days, and with Spring Break being one of the busiest times of year, they will be harder to come by only a few months away. Not sure how many in your party, which will also be a factor. For those you want that come up unavailable, you can register for a free account on Touring Plans, and use their reservation finder, which you can add 2 requests at a time, and they will send a text when one pops up. You try to jump on and grab it, and if you don't get it, just reset your search, or if you do, can add a new one. You can also watch the Cancelled ADR thread for your month here on the Restaurant forum to see if someone is cancelling one you need and try to coordinate with them to grab it when they are dropping. And of course keep trying especially the couple days before, and night before as people cancel to avoid fees(everything now is under a cc guarantee, so if no show they can charge $10/pp). 30 day mark also good time to check if people cancel trips before pay off is due.
For new restaurants, in MK there is BOG(Be our Guest) - opened at end of 2012 I believe, so guessing new to you. This is Beast's castle, really well themed so great to get in to see, and is a quick service for lunch and brft(lunch is better value) but you still need a reservation for this one, and can be hard to get. Dinner is now a signature meal(2 credits on
DDP) but you get to meet the Beast - also very hard to get. They also added Skippers Canteen in Adventureland, themed after Jungle Cruise. You can check out menus on app or website to see if it would appeal to you.
At AK there is a new QS inside Pandora, Satuli Canteen, and Tiffin's for TS outside of that area. Again check menus for your preference in cuisine and pricing.
At HS I don't think there is any new TS since then, but Hollywood & Vine now only has Disney Jr characters at brft, and has Minnie's Seasonal Dining at lunch/dinner - Mickey, Minnie, Daisy, and Donald wearing outfits fit for each season/theme throughout the year. You can also get a Fantasmic package here with reserved seating area for the show(also harder to find as it gets closer).
Don't think there is anything new for TS at Epcot - I am sure someone will jump in if I am forgetting. Outside on the Boardwalk at Trattoria Al Forna, there is Bon Voyage brft, with Rapunzel, Flynn, Ariel, and Eric. It is open from 7:30-12 so can eat early or late, but also popular and only for brft so can be less available.
At WL they just switched Artist's Point to Storybook Dining with Snow White, Dopey, Grumpy, and photo with Evil Queen. Very hard to get as it is new and only for dinner, and rarer characters as well.
Since they have redone Downtown Disney into Disney Springs, there are many new restaurants there which you could look up on your app.
For now, I'd decide which park you want to be in each day to prepare for 30 day FP, and try to find restaurants you want that are available in those parks or surrounding resorts. You could grab any that are open now, and then keep trying for your top pics as it gets closer, using the techniques I mentioned above. Things do pop up as people change plans.
Same will be true for FP at 30 days - some will be taken that you want, but just keep checking, even day of as things pop up. Also, if you are up for doing Rope Drop, can get some of the most popular rides done early that you don't have a FP for and good strategy for Spring Break crowds anyway to do more with shorter lines and use FP in early afternoon as it gets more crowded. Then you can try for 4th, 5th, etc. in the afternoon or evening, or if you hop to second park. Pack your patience as they say - tough if you are a planner like I am, but you will be back in Disney so focus on the fun you will have with whatever you end up with!
