Bernier has too many skeletons (and mistresses) in his closet, never made it to BC from my recollection.
O'Toole is a viable choice and realistic candidate but isn't bilingual. No matter what the ROC may think, the Quebec vote is necessary to win a majority, never made it to BC from my recollection.
Scheer is bilingual, is of the same vintage as Trudeau, has a solid character, has political experience, and is favoured by a broad range of conservatives, isn't a loud mouth but sells his product with fact - not fiction, and is one of the very few candidates who made it to smaller communities.