The selection sequence is important. The BCS doesn't look at the overall group of teams and select 3 of 4 - each bowl looks out for themselves. In your scenario:
1) Rose Bowl gets Wisconsin and TCU, without any options
2) Sugar gets to replace Auburn, and takes hometown SEC-team #5 LSU, and there's nothing wrong with them doing that.
3) Sugar then selects the first at-large pick. They take tOSU - the biggest name and fanbase available for tourism, ticket sales, and TV Ratings.
4) Then the Orange has to select an opponent for Va Tech - they won't select Boise State since the teams already played, so they take the Okie-State-Nebraska loser or Stanford.
5) Then the Fiesta is stuck with the Big East winner to face the Big XII champion - and they have no selection options.
In your scenario, it's all up to to which 3 teams the Sugar and Orange prefer, and LSU and Ohio State will be two of the three, assuming they each only have 1 loss. If the Sugar Bowl pulls a surprise and takes Boise State or Stanford to face LSU, the Orange would be doing cartwheels at the chance to take Ohio State, which hasn't been there since the late '70s.
So don't worry about tOSU being stiffed in the selection process - if the Buckeyes win their last two games, they'll be in a BCS Bowl.