1: It's up to each and every Muslim how to "deal" with it. There are no clear references to her age outside of Hadith written long after they died. Do you find it objectionable, and why?
2: It is a Hadith construction only loosely based on the Quran.
3: Not sure what context you mean, but the Quran implies the whole world will eventually embrace Islam, thus dominating it. It does not sanctify Muslims ruling over non-Muslims.
4: Nothing!
5: They would pray according to whatever they consider a "day", presumably guided by their sleep pattern, or you can always use the time in Mecca for reference, as those who live in midnight sun areas do during Ramadan.
6: The Quran rules against irresponsible, parasitic and criminal behaviour by immigrants. Real Islam doesn't threaten native cultures, unfortunately it's given a bad name by, among other things, Saudis founding extremely conservative Mosques in many Western countries that convince Muslims living there (who weren't previously of that mindset) to hate westerners, refuse to learn their language, lie about their "refugee" status for governement handouts, demand compensation and special treatment from workplaces & schools for "traditions" that don't even exist, etc.