Keeps 3 days refrigerated. Sliced cold it's very good in sandwiches and salads, which beats reheating — lean pork dries out quickly the second time. If you do reheat, cover it and use low heat.
Yes. The USDA lowered the recommendation from 160°F to 145°F plus a 3-minute rest in 2011. A blush of pink at that temperature is expected and safe.
Tenderloin is a small narrow muscle of a pound or two, very lean and quick-cooking. Loin is a much larger roast needing slower cooking. They aren't interchangeable without adjusting time.
Silverskin. Slide a knife under it and pull it off — it doesn't render and turns tough and chewy if left on.