After fixing a typo in the pin numbering in the overlay and a newly introduced solder bridge between the int and SCK pin, I can now talk to the cybergear. 

My overlay now looks like this:

[cm5]

dtparam=spi=on
dtoverlay=dwc2,dr_mode=host
dtparam=ant1
dtoverlay=spi0-1cs,cs0_pin=8,sclk_pin=11,miso_pin=9,mosi_pin=10
dtoverlay=gpio-pullup,gpiopin=5
dtoverlay=mcp2515-can0,oscillator=16000000,cs_pin=8,sclk_pin=11,miso_pin=9,mosi_pin=10,interrupt=5

(I have also disabled any configurations that might conflict with my SPI pinout)

My TODO list so far consist of the following items:

• Add a connection between the MCP INT pin and free GPIO on the CM5 header
• Fix the Dynamixel side of the board (single node net for DXL_DIR signal)
• (Not sure if this is necessary or not) Add a (NP) pullup option for the INT signal
• (maybe) wired ethernet option (ssh over bad wifi can be rather frustrating)
• 3.3V led indicator
• Option for active PWM cooler
• Break out a few more GPIO, 3.3V, GND and maybe I2C for future proofing
• ...

I can now start working on testing the IMU :)