Can you use the same syringe on the cheek/lips?

If you want the get the most out of two syringes of fillers, I would recommend using one 1.5cc of Radiesse plus to split between the two cheeks and using a 1cc of hyaluronic acid filler like Restylane or Juvederm for the lips. A skilled injector can get you noticeable but subtle results if the proper fillers are injected strategically. If you want to get even better results without using too much filler, you should consider having the filler combined with Platelet Rich Plasma (Vampire Facelift). 

Technically yes you can but the problem is that fillers used in the cheeks are thicker than ones used in the lips.