We just came back from our 2nd trip there last week. Its very different from WDW and in my opinion much easier to get around.
As far as dining is concerned:
I highly recommend doing Trader Sams. We had an awesome lunch there on our last day.
Need to get corn dogs on Main Street right next to The Plaza Inn.
Beignets and mint juleps at the French Market are great, and we found the food there to be some of the best QS in Disneyland.
Pizza Planet in TL was OK, and Red Rose Taverne was not too bad.
As far as TS goes, we did not have a great experience at either River Belle Terrance or Blue Bayou.
In DCA, we really liked Carthay Circle, but did not care for the Wine Country Trattoria.
A great treat in DCA is Clarabelle's on BVS. The Oswald was awesome.
Since you're doing the party, you may be pressed for time, but given the other two days are weekdays, you should be able to cover both parks easily, especially given that you have MP, which we used both visits.
I would recommend going at rope drop to DL and getting most of the unique fantasyland and tomorrowland rides knocked out early since they do not have FP. Then I would head over to NO and get Pirates, HM and Pooh done. In the meantime, you can easily book the FP for the mountains (SM, BTMR, SM) and IJ.
For DCA, try to get the FP for RSR early and ride GOTG at rope drop and then do MI to finish up that corner. With FP you can hit most of the unique stuff at your leisure.
Enjoy! We really appreciated the ability to move between the parks, so don't forget you can quickly jump between them if you can get FP for rides or dining reservations which don't line up with your original park plans.