Can I use 2 10uF instead of one 22uF for voltage regulator?
Two 10uF would probably be better, due to them likely having lower ESR or equivalent series resistance. If it calls for ceramic, stick to ceramic. Don't change type of capacitor, as the different types can have drastically different ESR. The only reason one 22uF would be better is because there is one less component to place on the PCB and might cost slightly less.