1) You literally just asked "HOW migrants from different continents arrived at our border?" Everything else you might have been asking in your head, but it did not make it to the post. I responded with the obvious, boats, because I alas am not a mind reader. Your concocted democratic coalition of trafficking, spying, gangbangers who all take the time to vote upon arrival when not doing their otherwise nefarious business is....well it's something.
2) Alright?
3) Modern travel is confoundingly cheap, even for the persecuted. Sad state of affairs that. I'm not entirely sure what you mean about the asylum claim process, could you clarify your concern or are you stating how you want asylum to work whether for legit or presumably non legit claims?
4) Possibly, but no other country on earth is the shining city on the hill and as I pointed out earlier, we've been tolerating it for about 150 years now. Gotta love tradition!