Yes, but Orion uses WebKit intentionally on desktop as well, unlike Chrome or Firefox which use their own engines on desktop but WebKit on iOS, so it's a bit different in this case.
Yes, at least outside of the EU. However, companies don't seem to be developing for it yet, probably due to the investment not being worth it until similar laws are more widespread. However, Orion in also on macOS, which does allow other engines. And Kagi is developing Orion for Linux and Windows.
