The upper chassis is a common Dynamic chassis, in the version they termed Dynaflex. What you call rotating axle housings are actually attached to the main chassis part via springs. The idea was to provide a form of suspension but in all honesty, it was a terrible design and worked poorly. These Dynaflex chassis worked a lot better if they were epoxied solid like the earlier Dynamic chassis.
Here's a couple pics of a Dynaflex chassis design, including one that has a hinge between the rear motor carrier and the guide tongue and front axle assembly.
Dynamic Models was a very prolific manufacturer of slot car chassis parts and cars in the '60s. To get an idea of the vast variety of stuff they produced, click HERE to see a series of posts made here by Sweden's Bertil Berggeren in 2010.
The slimline "chassis" is actually just a motor with a built-in rear axle carrier. Never knew much about these, as they were already obsolete when I got involved in the hobby; there were several companies than made motors like this. One of the other sharp slot car historians here will have to ID it for you.