There is absolutely no way that the Rats would allow the US to build such ships.
They don't know...got a friend, naval Architect, working on design of a stealth composite attack boat now.
Not sure we would want to anyway. They don't look very big, and that's fine for the Swedish Navy. Maybe not so good for ours.
How many tons do these stealth ships displace? How do they handle heavy weather? How long can they stay on station without resupply and refueling?
Smaller ships tend to be less stable and more susceptible to wind and wave action in the open ocean. They also tend to have shorter range. Not a problem for the Swedes, who are rarely far from a Swedish port or convenient fjord. The US Navy has ships in every ocean, and ships can be stationed thousands of miles from a friendly port.
There may be a place for such vessels (littoral combat, maybe) but not as front-line vessels.