Hello there! I am so excited that you are close to your trip! Honestly, on the walk back to our hotel late at night after the fireworks (I'd say about 11:30ish pm) I don't remember ever seeing too many stores open in DtD, with the exception of the actual WoD store. I'd say that I often saw that one open until 12, don't forget that I've only been during the summer busy season.
I LOVE La Brea Bakery but mostly for breakfast, they have the YUMMIEST chocolate coissants & during the later times in the morning it can get really busy. We NEVER had any long lines there early in the morning. I've never eaten there for dinner but they do have a cute outdoor patio area with tables & outdoor heaters.
Disneyland Resort - La Brea Bakery That link DOES list it available for dinner so I am assuming you should be able to do that.