Why would Orton drop down to IC Level? That doesn't make any sence, imo. Orton is a main eventer and should stay there.
As for Raw tonight, it is a possiblity that WWE could take Edge/Orton out of the MITB match, but if they were to face off at WM, I think it would be very rushed and a last minute decision. I'd much rather see them both take part in the MITB match and then turn on eachother, leading up to a match at Backlash, or somewhere else down the road.
I didn't hear the announcement that the final MITB spot would be determined tonight on Raw, but if it is, then I am intruiged to see how they add Orton into the mix. Maybe Raw will feature a 'Last Chance MITB Battle Royale' tonight, where Orton eliminates everyone and it therefore added to the match. This could take place at the start of the show, giving Orton enough time to 'recover' for his match against HBK.
This would also see two MITB participants facing off against the Raw WM main event on Raw (in singles matches). Ironic ... or well booked? I think so.