One week in "on the clock" at both jobs. As expected, potential for meeting conflicts seems like it is extremely limited.
I've learned that D1' and D2' have more in common with D1 and D2 than originally suspected. Both pairs have worked together for 10+ years and moved from one company to another as pairs. Also, both pairs consist of one member who is more management oriented and one who is more technically oriented.
Where they differ is competency. D1' and D2' are operating at a much higher level/larger scale. They are powered up versions of D1 and D2 in basically every way.
During new job virtual team meeting, D1' was at a standing desk and doing some pacing and some squeezing and bouncing of a rubber ball. This makes me hopeful that the rubber band thing was more ADHD than anger management.