I think Bayern Leverkusen will direct most of their energy on the bundesLiga because if they actually succeed it would be one hell of an achievement because it's been long that any team different win their league and that's why Bayern Leverkusen are very focus in their league and they are also doing well too because they have maintained their first position for sometime now.
The Bundesliga will probably be the top priority for Leverkusen, because there they will break the long history of Bayern Munich's achievements, while they will also create new history in the Bundesliga competition. But they will definitely have the Europa League as their target as well, and they will take it one match at a time.
This season is their big chance to win the Europa League, it is not easy for a team to be a favorite every season unless they can perform consistently every season. One more thing, they not only recorded without defeat in the Bundesliga, but in the European League they also did the same thing.