There isn't an abandoned house in Sunburst Island because that chapter is not fully implemented yet. It'll be implemented in the upcoming expansion of the Beta 15.
As for Ramuh dissappearing in Kanto, are you sure you're playing on a clean savefile in the latest release of the hack (Beta 15.4)?
Pre-Patched ROMs are a no-go.
In any case, the beta ends after winning the Orange Cup. You say you "got the championship of the orange region", so I'm assuming you mean that you won the Orange Cup, so there isn't much else for you to do.
Beat the Lv255 matches, get any items or Pokémon you missed, complete any bonus chapters you may have missed, and that's pretty much it really.
As for Ramuh dissappearing in Kanto, are you sure you're playing on a clean savefile in the latest release of the hack (Beta 15.4)?
Pre-Patched ROMs are a no-go.
In any case, the beta ends after winning the Orange Cup. You say you "got the championship of the orange region", so I'm assuming you mean that you won the Orange Cup, so there isn't much else for you to do.
Beat the Lv255 matches, get any items or Pokémon you missed, complete any bonus chapters you may have missed, and that's pretty much it really.