Regarding Dortmund's chances for the 4th place:
Freiburg is almost guaranteed to lose at least one game as they are playing against Leverkusen and Eintracht.
Leipzig is playing against Bayern, so also likely to lose points.
Dortmund has a big chance of jumping into the 4th place, but the big question is whether Leverkusen will play at their 100% and if not, will they also go easy on Freiburg?
There are some theories that some clubs sometimes give other teams favours and expect them to return them later. Also, from the wider Bundesliga perspective, having Dortmund in the Champions League instead of Freiburg or Leipzig is much more preferred for German football as a whole.