Yes, repeat per song works: You search for the song (the easiest way to do this is to go through the directories and find it that way). Then go to the menu (button below) and select "Repeat: Song" (other options: Off, All).
If you want to play a certain song repeatedly in an endless loop, it is advisable to create a playlist (m3u).
Charging is possible via USB, i.e. even without a PC.

The player can repeat per song or for all songs, even random mode is possible.
The player has a micro-USB connection and can therefore be charged with any micro-USB charging cable.