Thinking about our breakfast options, thanks for the earlier suggestions!
Is Garden Grove a table service meal? Do we need reservations for breakfast?
Will we walk past the Boardwalk Deli on our way to EPCOT?
1. We did grab and go at the Swan. Just off the lobby on the way to elevators is Java Bar. It was quick, easy, and the food was very good if a little $$. We mostly do continental. At the Dolphin, Fuel has lots of options. the SR has a similar place. It is small, but what they had looked very good.
When we stayed at SR, we actually did the continental breakfast via room service. It was great, because we were able to get it delivered at 6:30am. With trying to book G+ at 7am, and many WDW places only opening at 7am, the room service was the most convenient breakfast we've had at WDW in the current era. One morning there was a mix-up - our fault- and we had to go down to the QS at SR to get our food, but that was also fast. WAY better than most WDW hotel quick serve places or trying to get food in the park. In the parks, you will often find long lines in the AM. The in-park Starbucks are especially backed-up in the morning.
2. We did not end up eating at Garden Grove, but I was told we would not - currently- need a reservation to get a table there. In 2019, you did. I think they offer a buffet, with a continental option or a hot/full buffet option.
3. Yes. At least if you are walking from Swan or SR and opt to walk by the Boardwalk. (You could also choose to cross the bridge and walk the YC side of the lagoon, but that is not the directiom most people go.) We have dined at the deli twice. If you are tight on time, they do mobile order. Ordering in person was relatively quick though, and in-person you have more ability to customize. The Mobile order is more take it or leave it. The pickles are good, but strong on the pickling. The first time we went was just after they opened, and the pastrami was very good, a leaner pastrami. On our more recent visit, the pastrami tasted good, but was rather greasy. The sandwiches were greasy to the point that grease dripped out the bottom. It was especially greasy sandwich with cheese+dressing on it. The chicken sandwich was very good and less greasy. Your preferences may differ, but we all agreed, if we were going to visit a 3rd time, we'd choose the chicken sandwich or else order the pastrami plain. Both breads were tasty. Both visits, the desserts were exceptional. Not a huge selection, but what they had was exceptional! Beautiful and delicious!
It is worth adding, in general, the Deli and pizza window are a short walk from the Swan. If you were coming from Hollywood Studio, it is only a short detour to visit the deli and other Boardwalk QS options. For that matter, the whole lagoon is easy to access. You can walk it or take the free shuttle boats around the lagoon to access any eateries at YC/BC/Swan/SR/Dolphin/Bwk.