Saati's reveals counter Sha and she also has the range to fight him if she gets the first shot. Having Seek (Increase the duration of Dead Ringer’s reveal on destruction by {0.5|0.5}s) on high levels hard counters him, especially Sand Trap.
most champions will have a hard time dealing with Io and Luna together, so don't engage them together instead try to single out Luna while Io isn't around, so when it comes time to kill Io she can't stun you or body block with Luna.
Androxus' reversal isn't able to counter either, Guardian Spirit stun or Begone but his damage per second and having burst damage allows him to clean up kills on Io fairly Quickly. This is not to say that Io cannot body block with Luna.
Koga can avoid Luna's stun so your best tool to handle him is to use Luna's large hitbox and healthpool to face tank his fire while taking chances to fire at him.