Apparently, this is a week-end job, probably, because I like the daylight in my workshop. And for the final glue-up I need someone to help handling the clamps etc.
I found an interesting way to fix lose joints, in this case a leg that is glued flat to the bottom frame, secured with dowels and a screw. There was no way to pull it out, and no surface to hammer on, so it stayed put, no matter how hard I tried to remove it. Then I used a flat spatula with hot water to work into the gaps and remove some of the remaining glue. The result: The glue rehardened and the leg is stable again. The final action will be adding more glue into the gaps and rocking the leg, so the glue can soften the original glue and get fill up all space.