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. 

You need a Minolta AF to Sony E/NEX adapter. The MD/MC Minolta mount is different from the AF mount, so the AF lenses don't physically fit the MD-NEX adapter. 

Could you please update us your full Minolta lens model ?as Minolta has MD MC and AF mount, K&F Concept MD-M4/3 is suitable for: Lens: Minolta MD MC Mount lens(not for Minolta AF mount: KF06.157) Camera: Micro 4/3 (MFT) mount mirrorless camera like Olympus PEN, OM-D series, Panasonic Lumix DMC-G1, G2, G3, G10, GX1, GH1, GH2, GF1, GF2, GF3, GF5, GH4, Panasonic AG-AF100 Mirrorless Digital Cameras, Black Magic Pocket Cinema Camera (BMPCC) 

MD-FX you are asking, the button you asked is a lens release button, when you want to take the lens off, you need to press this button down, hope it helps and please trust to purchase. 

Yes, it is indeed Nikon f mount.