Yes, all brand paintball guns use a tank or other source of pressure.
Paintball guns can use Co2 from any company, they are all built the same. You can find valved tanks and 12 gram's at sporting stores, paintball fields and proshops.
No. There are no urban areas that allow paintball.
Not completely sure how you could use a balloon instead of a paintball marker. Though paintball is known for its guns therefore no.
Nearly everything. Paintball guns are fired through the use of air or CO2. Also they shoot only paint. bb Guns shoot pellets, and look completely different then most paintball guns.
All paintball guns require propellant, but some use HPA or high pressure air, instead. HPA tanks are more expensive and holds less shots, but are significantly more consistent (accurate) and easier and cheaper to refill. You can also tell how much you have left on a HPA tank.
size is all personal preference, you can get something as small as a 9oz or up to a 24oz co2 tank, the larger the tank is the more shots you will get off of it but the heavier and larger it will be
If you aren't mature enough to play paintball, you aren't mature enough to use firearms. There is no way you can confuse paintball or vidoegames or airsoft for what you should be doing with actual guns, unless you are not old enough to use guns.
Paintball guns are not classified by their roles. If you ask the ref if you can use two guns that's fine. Having two guns (with basically the same range) is a waste and will slow you down.
No, you should use only paintball specific of air tool lubricant.
tanks machine guns
You can use co2 tanks if they are the anti-syphon tanks or if you put that on your tank put even then they are not recommended.
Most paintball guns use an above hopper instead of magazines or clips like firearms. The standard hopper holds 200 rounds. Most magazines for paintball sim-markers are 30 rounds. No paintball guns use clips.