in pokemon emerald you don't have to check the pokeball for the rival to find you can just go back downstairs and they would just walk in
in the gen 4 games if you give yourself a full party of pokemon before picking a starter then the starter you choose when the scene comes just vanishes from the game entirely and instead Rowan (i think the professors aide too) will just mention the first pokemon in your party instead
and lastly i dont remember if this was in rse or it was oras specific but if you avoid your rival in rustboro by teleporting to petalburg (you need to have abra and also have never set foot inside of the pokemon center in rustboro) you would catch them leaving mr briney's house instead and there's i think a unique dialogue for it

>>714191630
Adventure 1 > Adventure 2