If I had to guess, maybe Dingwall will have their Chinese factory send them a number of "kits" for the US market. Unassembled instruments that still need to be put together and completed so they can technically be called "Built in Canada." Manufactured, fabricated, built, and where it happens is all largely a matter of semantics.
I'm sure they also sell to US dealers at a dealer discount rate, likely between 15% and 30%. So, ultimately, if Dingwall does what I said above, the price increase would only be reflective of the dealers increased purchase cost. Not great for the end purchaser, but not likely anywhere as bad as 150% on top of 25%. A lot of companies will be looking for these sorts of loop holes.
I also ultimately suspect and hope there will be some sort deal hammered out with Canada and Mexico and the EU in the end.
However, I believe any sort of settlement with China is far less likely.