The ones who did the voices of the Sinnoh Elite 4 and their Pokemon would include Christopher Adams who did the voice of Aaron, Michele Knotz did the voice of his Beautifly, Konishi Katsuyuki did the voice of his Skorupi and Chinami Nishimura who did the voice of his Vespiquen, Mary O'Brady who did the voice of Bertha and Marc Thompson did the voice of her Gliscor and Tom Wayland did the voices of her Golem and Hippowdon and Tom Wayland did the voice of Flint and Bill Rogers does the voice of Flint's Infernape.
The actors that did the voices of Sinnoh's Elite Four were Christopher C. Adams, who did the voice of Aaron, Mary O' Brady, who voiced Bertha, Flint's voice belongs to Tom Wayland and finally David Lapkin as Lucian.
No but you can catch many of the Pokemon in Sinnoh after you beat the Elite 4
The Pokemon League after beating the Elite 4.
See every Pokemon in the Sinnoh Dex and beat the Elite 4 The Elite 4 provides many Pokemon to see for the Sinnoh Dex that no one else has. Good tip (Dont skip trainer battles. Although they are annoying, they carry most of the Sinnoh Dex Pokemon)
Get the National Pokedex by seeing every Pokemon in the Sinnoh Pokedex
after beating the elite 4 and have all 151 pokemon's seen in the sinnoh dex
You make all their Pokemon faint and you should vary the Pokemon to their weakness types
No Ash is not going to battle the Sinnoh Elite 4.
Yes, but you need to get the national dex first by beating the elite 4 once
see all the Pokemon in sinnoh region go to pro birch and he will give you national dex
I think it was the base of the Elite 4 waterfall, search for it on your poketch... it is also in sinnoh underground.
If you've beeten the elite 4 and finished sinnoh pokedex (all 150 sinnoh Pokemon) they should leave.