The compressor has an air filter that needs to be replaced periodically and the tank needs moisture drained out the bottom.
Sand blasting guns guns are cheap. I have one from HF (blasting guns are not critical like paint guns) and it does the job fine. Again, the CFM output of your compressor will struggle to keep up with the requirements of the guns. Get the smallest *** and don't shoot continuously for too long or you can burn out your compressor. That compressor is fine for spraying bike frames. But for painting something larger (like a small car) that compressor would not be able to keep up with that g-n.
The method of paint removal depends on the frame material. Blasting is great for steel, but aluminum is too soft and could be damaged by blasting. Chemical removal is easy and effective but precautions need to be taken to protect your skin and lungs. Sanding is more labor intensive. But also keep in mind that you don't always have to go down to the bare metal. If the factory paint is in good condition then it only needs to be scuffed up with 400-600 grit paper or scotch pad to give it enough tooth for adherence. If it looks like anything other than a factory paint job then taking it down to bare metal is safest.