I think that the best spot that Boston College can have in the ACC is fourth (they will be fourth if Wake Forest wins or if Georgia Tech wins). Am I right or wrong?

Tie-breakers. I don't know the whole break down of the whole thing. Heard it on ESPN Sportcenter.

It doesn't matter. While I think BC would be 4th or 5th given the tie-breaker system, bowls will select teams by choice, not by hard rankings.
Meaning: regardless of who wins Dec 2, the loser does not automatically get the second place bowl (Chik-Fil-A). In all likelihood, VT will be asked to go to that bowl regardless of the championship game's outcome, because that's who the bowl organizers want.
All indications I have heard have BC going to either the Gator bowl or the Champ Sports bowl, but Music City and Meineke remain possibilities.