Lidgar
Gongfarmer
One way to deal with giving humanoids different armor and weapon options on the fly is create tables that show the changes to AC and attacks/damage. See the appendix to this document:
Random Encounters: Dungeon Levels 1-3 - Dungeon Masters Guild | Dungeon Masters Guild
Random Encounters: Dungeon Levels 1-3 - Dungeon Masters Guild | Dungeon Masters Guild