When a creature goes unconscious it almost always goes Prone, Helpless, Unconscious, soon Flat-Footed and usually Dying or sleeping. see AoN Conditions (Combat). The text stating that it drops any held item isn't specifically declared in that text but I believe it is on Paizo's published "Condition Cards". I'm also sure there are several old posts on this exact topic. The previous poster noted the locked gauntlet.
Okay, the process is Living->Dead->Reanimated*->Undead->(cause problems for the living)->Destroyed. Once Destroyed the body can not be used for regular reanimation (yes, possibly other uses as twisty are the ways of magic) and likely your sensible GM would say "No" to most other magical uses. Destroyed is destroyed. How that descriptively works is up to your GM.
Conclusively, In the spell description of Animate Dead is the text, "The undead can be made to follow you, or they can be made to remain in an area and attack any creature (or just a specific kind of creature) entering the place. They remain animated until they are destroyed. A destroyed skeleton or zombie can't be animated again."
Again, there will be old posts on this topic. (* usually a magical process, sometimes just Evil)
My Advice on rules is to search the FAQs, then search and read Archive of Nethys (doesn't always have everything), and then read d20pfsrd for an opinion (as they sometimes change stuff). If something is banned in PFS it is an indication that it requires some GM oversight or tweaking, may affect Wealth by Level, and may be overpowered for its assigned level/requirements. Amusingly they didn't ban seriously underpowered rules/spells/items.
