Identifying an unmarked SMD capacitor and chip
Measuring capacitance in situ is unreliable and inconsistent. You should remove the part and measure the component directly. 

Those are ceramic chip capacitors (99% Confidence). And they are not polarized. 

This kind of el-cheapo 5V stepdowns use a common circuit design. It is probably easier to go to the source material (design guides) and not reverse engineer.