Yes. you may need a neck adapter though.
No. Paintball pistols cost as much, if not more as starter guns. besides that, they have low ball capacity and must change clips after they run out of 10 balls or so. Also they run on 12 gram co2, which is expensive to run as a main marker.
You can find the parts on the linked page.
When someone is just doing paintball for the first time they need a paintball gun that is easy to use and light. The recommended one is a Tippman 98. Any of the variants will be good.
yes
The Piranha USP. Its only $70. most pistols cost over $200.
The first paintball guns were used to mark cattle. They resembled a pistol.
No. Viewloader is notorious for low quality products that have many malfunctions along with being generally bad in every category but price.
Walmart carries small pump guns that could be used as sidearms.
Which model? If it is the t9 or t8 pistol then you have to buy an adapter for a 20 oz tank.
You can remove the 12 gram co2 can by releasing the magazine and unscrewing it. Remember that you do not get to save the gas, as it is all lost once you remove it.
I think you need to rephrase your question. Do you mean Firearm, Air soft, BB gun, Pellet gun or Paintball. It also depends on where you live.
Yes, most sear tripping (mechanical, tippmann style) paintball guns, however, will run, with some fine right tuning, on either CO2 or compressed air. Most blowbacks (tippmann, spyder, azodin, bt) are "meant" to run on C02 and may run into problems with HPA without some internal adjustment. With very few exceptions (SP1 and SP vibe) spool vavle markers cannot run on CO2, and those that can, need an anti siphon tank so they do not get liquid into their valve. Almost every other gun will run great on HPA.