In Granada:
Los Diamantés has great seafood tapas. The location on Pl Nueva offers table seating (very casual at shared long tables). Other locations might be bar or table.
For a very nice lunch or dinner, Carmen de Aben Humeya in the Albaicin. Very good food, upscale, and beautiful views of the Alhambra (nice gardens, too).
Falafel is really good in Granada. Try it from any hole-in-the-wall falafel or kebab shop.
All of the places you are visiting are great for walking around, snooping out what looks/smells good, and popping in for a drink and a tapa. Remember, especially in Granada, don’t order a tapa from the menu right off — wait to see if and what they bring with your drink (which does not need to be alcoholic). If you don’t love it, move on and try someplace else.
If you like food tours, we have done them with Spain Food Sherpas and Granada Tapas Tours. Both were excellent.