If we signed Bichette with the express purpose of playing 3B...
I could see him as a 1B or 1A to Bregman.
Not as good OBP, but much younger and therefore less Age Risk Exposure.
I could definitely get on board with that, thinking in those terms.
And... he could even be signed (with his knowledge) as a SS/3B... holding SS until McGonigle is ready for MLB.
That gives less pressure to force McGonigle onto Detroit's roster "RIGHT NOW!!!"... just in case he is not quite yet ready.
And if Rainer moves quickly, or if/when he is ready for Detroit... The best SS of the 3 holds the spot, the other two are at 2B and 3B,