Any USB charger will do. As long as it accepts European voltages, your phone charger will work. Super handy if you want to charge while driving. 

I doubt it: not because of their diameter, but because they are super- slim so no obvious place for a lens cap to attach to. This said, they screw on and off with minimal effort, so I take them (and the filter system off) off before transporting the camera to a new location. 

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) 

No, this adapter is for the older manual focus Minolta Rokkor MC and MD lenses. If you want to autofocus and aperture control you will need the Sony LA-EA4. (the lower cost Sony LA-EA3 will electronically connect A mount lenses but you will have to manually focus.) 

it will work with a3000 and a3500. use this adapter with minolta md or minolta sr lenses