What's the best way to reheat grilled shrimp
Since grilled shrimp only require 2-3 minutes per side to throughly cook on a preheated medium-high grill, skip the reheating steps and all that time and extral effort all together. Just cook them once. It would be only worthwhile to cook and reheat if the initial cooking step took condiderably longer

The risk of overcooking during reheating with such a short total cook time is extremely high! No one enjoys tough, chewy over-cooked food

Additionately, guests love to help at a party; even if it performing trash duty or washing dishes. I'll bet if you ask the 50 or so guests for volunteers to cook the shrimp that you'll have over 40% of them step up to do it.