Bishop Guerard was only arguably the top theologian in the Church prior to Vatican II.
I'm curious: what would qualify Des Lauriers as a contender for top theologian prior to Vatican 2? I've heard similar things before, but it seems quite exaggerated. His greatest theological achievement that I know of was participating in the Ponfitical Commison in preparation for the dogma of the Assumption. But it was Fr Charles Balic who headed this commision, and also the International Scotistic Commission in addition to founding the Pontifical Academy of Mary.
I dont mean to belittle Des Lauriers here, but it seems difficult to imagine his name even appearing alongside names like Balic, Roschini, Ciappi, Lagrange, Bonnefoy, etc prior to the council. I could see arguing thay he was the most eminent theologian AFTER the council since so few rejected vatican 2... but I've only personally seen his name once in an obscure footnote in any pre-Vatican 2 theological text. if you have some further knowledge on his works and publications prior to Vatican 2 I would love to look into them. Thanks