Hi picclock,
Thanks for the info re glues. I used a contact adhesive to try to glue the cork to the heatbed. I know it is on the borderline temperature-wise, but it is a try-out. As yo8u perhaps saw on the previous images, I have used thermal paste for PD processors to connect the heatbed thermistor to the bed and the glass plate will be flat on (at least from start .....)
The heatbed is now attached to the plywood baseboard on the Y axis.
I started with a piece of the left-over stainless 8mm bar.

From that bar I made three top hat-like bushings that I glued into the ply at the proper places for the screws with the springs.

To avoid having to make a 3mm thread all the way through the 13 mm bushing I drilled it out about half way from the bottom. Threading went very nice and then the bushings were glued in place in the ply board.

With the heatbed in place I started with how to lay the cabling so it does not get itself entangled in the machine. A combination of small plastic cable guides (the white ones on the base board), and spiral tubing, I think I got a setup that may work.

The white cable guides are good for just laying the cables inside to stay out of the way. They are also well protected from mechanical happenings.
The cables from the X-axis motor and its end switch got their own piece of plastic spiral tubing. The cables are held together in the end close to the motor and the spiral then enters a 10mm hole in the portal to guide them towards the electronics on the back side. Did this as it turned out that the length of the cables were is some cases just a tad short compared to what could have been for ease.
I also did the same with cables for the extruder carrier with all of its cables The heatend, temp sensor, fan, and extruder motor. They got an own 10mm hole right beside the first one.
This way I can secure the cables on the rear side nice and tidy and no cables will run over the portal which may obstruct the filament guide tube.
While re-reading your post I noticed that I did not answer your question at the end, sorry. I used two aluminium connector pieces which are slit in spiral form to allow angular differences between the Z axis motor and the threaded rod for the movement. You can see them on the image above right above the Z axis motors. So far I have not noticed any problems with that. The coupling is a standard part that was included in the mechanics kit I ordered. Since the motor and the threaded rod only have a fixed position at the motor mount, the other is at the nut for lifting the X axis movement and that point continuously moves depending on where in height the X axis is at the moment. So I think there are not much hat can go wrong angle wise.
When it comes to the end stops, I have chosen them to be placed as follows:
X axis - at the left hand side and the micr switch triggs against the stepper housing.
Y axis - at the left smooth bar triggering against the left bearing housing under the board.
Z axis - to the left, below the X axis motor mount triggering against the underside of the motor mount.
I have only used three micro switches so far but am thinking of using three more to definately define the both ends of the travel for all axis.
So far so good today.
/Peter