Yes. Disc front/drum rear has been the most common configuration for many years, though disc front and rear is becoming more common among the manufacturers.
A brake system brakes.
The service brake is the one which applies the brakes - the emergency brake system is the system which releases the spring brakes.
Yes, bleeding the brakes removes air bubbles that might be left in the system, especially in the brake lines!If not done every time the brake system is worked on the brakes will be unreliable and unsafe!
The brake pedal has nothing to do with it. If air is in the system then bleed the brakes.
S-cam brakes.
hydraulic brake booster (power brakes)
It's a dual circuit air brake system. Most use S-cam foundation brakes, although some use disc brakes or piston brakes.
The brake booster is part of the power brake system.
A parking brake system is not required if your service brakes are fully self-locking. Air brake systems (on semis, for instance) hold the brakes open only when air is supplied. If you blow the air the brakes lock under spring pressure.
faulty master brake system
On an air brake system, the brake chamber is what actuates the air brakes... it converts air pressure to mechanical force, either turning an S-cam (on foundation brakes), or actuating a caliper (on disc brakes).
Your brake fluid is how the brake system converts mechanical force of your foot on the brake pedal, into hydraulic force that applies your brakes. Without fluid, your hydraulic brakes will not function.