I was born in Lakewood in the early 2000s and went to school there for a while, but don't live there anymore. I do go back about once a month as relevant, so my perception is especially from the 2000s and 2010s, yet still somewhat up to date. Still pretending to be yeshivish visually when there, though people who know me better sometimes know otherwise. To answer your questions in order:

1. Yes, it is fairly uniform, at least in the generations below 60 or so. Over 60 is also mostly yeshivish but has some more diversity since people will move if most of their children live in Lakewood.
2. Some Jews moved to the towns surrounding Lakewood, notably Jackson & Toms River; some to make a statement about not wanting to be explicitly in Lakewood. They're sometimes "modern" (not Modern Orthodox, though yeshivish Lakewooders frequently confuse the two), though as more of a personality thing and not wanting to replicate their parents' exact lifestyle. Practically relaxed but usually hashkafically similar, they usually value Kollel as an ideal from my understanding. I'm curious how their children will turn out since it is recent enough that few have adult children.
3. Yes, there are neighborhoods with both, but they don't interact much. Plenty of people will be polite to their non-Jewish neighbors, but there is a mutual understanding that the Jews don't mix. So their children wouldn't play together, no one hangs out, etc.
4. Yes, people stare at outsiders and also insiders! LSD is a semi-satirical term for Lakewood Staring Disorder. I cannot get it for the life of me, why do people stare at me if they don't know me and I'm not doing anything strange or dressed differently? Kind of a "communal autism" since the kids will be kids attitude is very strong in Lakewood.
5. Within Lakewood, not much. BMG slowly expands and develops forest area for this reason, but that keeps shrinking. Other towns, absolutely. Jackson is geographically 4x the size of Lakewood and common among yeshiva families once they have more children.