iMO, you really shouldn't build a permanent solution on a breadboard, wires are bound to get loose.
These will provide clear from the USB/Ethernet ports if that is what you mean by fitting the Coupé:
https://shop.pimoroni.com/products/adafruit-perma-proto-hat-for-pi-mini-kit
or
https://shop.pimoroni.com/products/protopal
You could even stick a breadboard on top if you really wanted to, though again, soldering in permanent position is what will give you the least trouble long term.