European iPhone owners are being shown a new pop-up screen listing alternatives to the Safari browser. The developers of the browsers shown on that screen are torn about the user experience.
I don't believe there's any issue actually building the app. However, the app store policies forbid them from shipping it or offering it as a side-loadable option.
Dunno yet. Probably depends on the outcome of current legal cases against commercial AI companies. Github/Microsoft was sued for example because of CoPilot being accused of using GPL licensed code without adhering to the provisions therein.