I am not sure as yet about the BEC, but I shall find out for you asap.
Power Cap, probably will have to, but the Tekin power cap is a small unit, selected so that it will sit on top of the ESC, the reason for this, is you can keep the leads very short, which also allows a smaller value capacitor to be used. The Power Cap is also a high quality unit, not a cheap 'off-the-shelf' cap.