One is for full format and the other for APS-C, whereby full format can also be operated on APS-C. 

K&F Concept 55mm variable ND filter you are asking, you mentioned your Minolta 24-70mm vintage lens is 55mm, just please go ahead to purchase, please do not worry about it. as long as the lens size and the filter size is the same, then works. hope this helps. 

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. 

Yes you can 

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)