Your bikes were probably made in China anyway.
Holland is an exception. The Dutch bikes are quite different and have no conventional brakes requiring the rider to pedal furiously backwards in order to avert a collision.

As you say, if freight is not an issue then bring them, you can always dispose of them here if you need to do so.
Yeah most of the stuff here in the US is made in China!
As far as I know when getting parts here in the US, the brand never mattered, it was more what size the bike was to get the right tire, chain, etc. But OK then if Holland is truly an exception then I won't worry.
Our bikes: a Giant from the cheapest end of the mountain bike range from over 10 years ago, and another one is a non-branded bike that was assembled as a hobby using parts bought separately from a bike store. Nothing special, as I said.
That detachable trailer will be useful.