Transfer your saves via a System Transfer to your friend hacked switch, and redeem the gifts in there via Switch Gift Data Manager, or activate the event flags directly via PKHeX. You can transfer your save file back after the process.
In v1.0 carts you can use glitches to reach Shaymin, but Darkrai would not appear unless the proper event flags are activated, which is not possible via glitches. That said, you can't load an updated save file to an older version of the game.
The only/suggested way is to use an hacked console, capable of going online (SysNand CFW, not EmuNand).