It would be political suicide for the Greens and, very likely for the FDP as well, to help Laschet and the CDU to retain power. Nobody here wants to see him as Chancellor, and yesterdays results reflect that quite clearly.
It's over for Laschet and the CDU, they just need a bit more time to let in sink in and come to grasp it.
Yes and no. I could well imagine that the CDU fires Laschet and someone else emerges, along the PR lines of "we understand that the people do not want Laschet, we are listening". Laschet is already losing control, as Ralph Brinkhaus wants to be re-elected as the parliamentary party leader for the Union, against Laschet whishes to only fulfill this role provisionary until it is clear if Laschet does become chancellor, or has to become the opposition leader (and that would be the parliamentary party leader of the Union, that is why this job is important).
FDP does make clear for years now that they need to see some of their projects realized and do not seem to care very much with whom they do it - the Union just seems more likely to allow that than the SPD.
The Greens have a bit of strategic thinking ahead: They in general could be able to overtake the SPD as the biggest leftist party, but they failed to do so this time. It will be close to impossible to overtake the SPD the next time when they now become the smaller partner in a coalition with the SPD. If the Union pays the prize to enable a lot of Green projects that could be a much stronger base for a future Green-dominated leftist coalition.
Both Greens and FDP want a fresh start for the country, they agree on that and might find a common understanding. If they do that, it just is the question which one of the two big parties bends over the most to allow them this. IF such a government works successfully, there is a chance for both Greens and FDP to become bigger at the cost of SPD and/or CDU, but the party who has a (successful) chancellor usually profits from it.