trash-in-game tips should be heavily updated, focused so it only talks about the things the player can currently do with their class and loadout, and then show up every respawn. if possible, make it context-heavy; did a player die from afterburn when you had a mad milk in your loadout? point out that it can douse the flames.
Uh holy yes. In-game tips while you're waiting to respawn, kind of like the ones on the loading screens of some games (StarCraft 2 & Warcraft 3 come to mind), relating to how you died previously or to your class in general. That would be amazing and super easy to implement.