In the progress log I'm seeing that weapon icons are coming. Personally I don't think icons are needed, and can be replaced by border highlighting the weapon in a unique color. This will give players all the info they need, while minimizing the visual footprint the functionality is going to add to the game.
Thinking command hud blue for the basic lmg, green for the shotgun, red for the flamethrower and purple for the grenade launcher.
As for the ammo/health packs, a simple white outline would be fine I think.