Well, well. I found my own answer to the HUD display.
I was snooping around in the console and found the commands for Day of Defeat V1.1. Not sure if they apply to other engines.
CL_HUD_AMMO 1
CL_HUD_HEALTH 1
CL_HUD_MSGS 2
CL_HUD_OBJECTIVES 1
CL_HUD_OBJTIMER 1
CL_HUD_REINFORCEMENTS 1
Change them to 0 and there will be no HUD displays.
These commands work for player and not spectator mode.
Got another problem though: it's the ZOOM.
Zoom is set 2X and I need 1X to match standard minimaps.
How to zoom to 1X at 1024 x 768??? What's the command??? Haven't found it yet.