Not exactly sure what you're trying to do, but the cartridges for pellet guns sometimes have oil in them to help the gun operate smoothly. Other than that, CO2 is CO2.
agreed. you need FOOD GRADE CO2 bulbs. the ones for seltzer water dispensers are usually cheaper than 'homebrew' labeled ones...provided they fit your hand charger.
I use mini kegs and no you cant. Chances are your mini keg wants 16gram c02 cargers. Paintball guns are 12gram,and most the industry ones (for soda bottles etc) are 9 gram. You cant use the 9gram ones they wont fit at all, the 12 gram ones "can" be adapted to fit with a stopper. Do NOT just bung tin foil in the end till its tight enough to make contact. There is a release valve at the end that needs to be clear for those first .05 of a second when you puncture the seal. If the valve isnt there, the threads tear off and the handle shoots across the room nearly killing SWMBO....trial and error
16 gram is the correct size for the housing. I recommend the threaded ones as the neck size is closer to the original. The non threaded ones can work as well, but they have a smaller neck that increases the possibility of a leak.
I got those at REI actually for my CO2 bike tire inflator, but they appear to be the same as the ones my local LHBS sells for about the same price. The inflator looks the same as the one my LHBS sells too. I am guessing that Genuine Innovations just packages based on specific use. I have also found the cartridges on Ebay and Amazon for as little as $1.10 per cartridge when buying in bulk. Just do a search for "16 CO2".