Yes, reheating notes are back - even though I know by web stats that not many people read them, I'm compulsive enough to need them.
Empanadas: These taste okay at room temperature, but best to be toasted in an oven at about 350-degrees, or in a toaster oven. They won't take long. They don't taste great cold.
Corben Sandwich: This here is an open faced sandwich (at least in the Hel's Kitchen interpretation). It's on a Portuguese Muffin which according to King Arthur Flour is a dense version of the English Muffin. They go on to give a recipe that is almost nothing like an English muffin in any respect except being bread and about the same diameter. Among other oddities, it rises three times and on the third time you place a weight on top of the muffins to prevent airiness. I assemble these sandwiches by toasting the muffin, heating the meat and jus in the microwave, pouring that on top and then dipping my fork in the mustard and apple butter when eating. I'm also the kind of person who orders salad dressing on the side at a restaurant and dips my fork in that while eating, so you can decide if my example is best. You could also spread these condiments on top of the hot beef. Someone from Miami could chime in with the actual correct way to eat a Corben.
Vegetarian Cubano: Be still my heart, I think this sandwich is lovely and I don't even like avocado. This will benefit from being griddled, grilled cheese style. I should remember to give you a little lime mayo for that purpose (I can't say I've been 100% on remembering that . . . it's only about two teaspoons of mayo and easy to forget). In any event, butter the outside of the bread with mayonnaise or butter, or brush liberally with olive oil and place it in a hot skillet until well browned, then flip. It's a thick sandwich so it takes a little while to heat through.
Yucca Root Latkes: Reheat these in a skillet with a nice slick of canola oil (or other neutral oil) in the bottom. It should be quite hot when you toss these in so that they crisp. It shouldn't take very long. If you don't want to get a skillet dirty, then sticking them in a hot oven or toaster oven on a pan top of their foil wrapper - unwrapped and unstacked - would work. You don't have to leave the foil wrapper on there, it just means you aren't left with a dirtied pan.
The lechon asado and the lentil soup are both reheatable by microwave or in a small saucepan.