I've tested something, and I can say  that multisig is seriously broken on at least Sparrow and coldcard. 
I'll try to document it in time. So anyone who likes to verify can do so.
Still waiting for the solution from Sparrow now. But does't look good , even if they can solve it somehow, it brings extra complexity to the whole thing (last thing we needed).
 

 I am curious what you mean with multisig is broken on Sparrow and Coldcard. 

 Any news about this? 

 Not yet. But for sure id'd one scenario that's f'd.
Had unfortunately no time to further investigate, personal stufd going on.
More soon. I wznt to document this thoughougly  

 Oh well. Curious to know about what you’ll find out here. Keep us posted 🫡 

 Unfortunately still zero time. Hellish week here.  I do what I can tomorrow  

 Oh yeah sure. Take your time 👊🏻 

 The thing that's possible broken or very broken is in such a state foenyezrs now, so a few days more won't matter :) 

 Few days won’t matter indeed ;)