In case those aboard don't get to these, from memory of my two recent cruises on Royal.
1. Lido (deck 16) has good views from indoors. Maybe 10 tables in Piazza (deck 5 in Vines and Good Spirits Bar).
2. 3 free venues, Alfredo's has pizza, salad, a few other items, trident: burgers, fries (the one time we got them they were nice and hot), tacos, hot dogs, chicken sandwiches and nearby is slice for a quick poolside pizza option. For menus, if no one posts them you should be able to google it and get current info, also see link below at #5).
3. Not that I know of but didn't travel with kids so may have missed something.
4. Not that I know of.
5. The menus on this website are pretty similar for most of what you are asking as far as I recall.
Discovery Princess Restaurant Guide With Menus - Eat Sleep Cruise
6. Medallion generally work pretty well for us. WiFi was usually pretty good but depends on itinerary and usage I believe.