Thunar or Pcmanfm are pretty good. They support pretty much all of the dbus calls(drag drop etc.). Only thing they lack is the support for GOA(GnomeOnlineAccounts a synch tool for common drives). Other than that they are on par with Nautilus feature wise. I think they are slightly faster too and allow custom commands.
I don't know a file manager with video player included. You can download mpv. It's a pretty lightweight video player.