I can't say anything for sure about Dortmund yet, but it's hard to say for Leverkusen. Bayern Munich is a balanced team in the Bundesliga who have a high chance of winning the title this season and if nothing happens, Bayern Munich will probably win the title. Because in terms of team strength, no team is close to them and it is not possible for any team to threaten Bayern Munich. But it is not the right time to make predictions and it is too early. For Dortmund, it will be possible but not easy.
I think that right now it’s not difficult to make a prediction about Bayern, even if you just evaluate their transfer activity during the off-season. Díaz is already showing that he will strengthen their attack. On the other hand, Sané and Müller have left, but I see Kompany as a coach who is ready for experiments and changes, and that works for Bayern. Dortmund, on the other hand, fall short of Bayern in many aspects, so I strongly doubt they will be able to compete with them this season.