Yes, our bodycam is equipped with a 1/4" mount thread, so you can mount it on your bicycle bracket. 

The Kiev Rangefinder Mount is not 39mm Leica Thread Mount compatible (L39). The Jupiter 8 Kiev mount version does not have a threaded mount, but more like an external bayonet mount. There are M39 versions of the Jupiter 8 lens in which you jet get an M39 to E mount adapter. 

No, only at one end and its fixed so ideally you need a ball joint as well 

The benefit of this adapter is that it’s suitable for Pentax DA lenses that don’t have an aperture ring. The silver ring on the adapter controls the aperture linkage on the back of the lens. Although a lens might typically have a aperture range of f2.8 to f22, the adapter only has 5 stops, and the real value of the aperture is guesswork, however a mft camera will have no trouble gaining the correct exposure. Lenses with their own aperture ring can still be used on this adapter, you just need to see the adapter to ‘open’. 

I have used one on a Sony a7 mkii.