1. No comment.
2. Make sure the Letter of Intent is signed physically, not e-signed. A copy of the physical signed letter is fine.
3. Like previously mentioned, just the bio page and the stamped pages. You do not need to send in blank pages. USCIS required one proof such as the US Passport or Birth Certificate, but I just sent in a copy of both.
4. Never married, so I never looked much into it, but USCIS mentions
5. No comment.
6. Recommended to include date, who is shown in the picture and who is who (e.g. from left to right), where the picture is taken, and what you are doing (e.g. enjoying a walk in the park at "city").
7. As mentioned previously, checks are no longer accepted by default.
Do what you see fit, but I printed my pictures in black and white on normal paper with no issues. Some people claims it has to be in color, but I assume it's because pictures weren't clear.
I just seperated sections using title pages, but no divider that pops out at the side. The packet has to be easy to disassemble. I used a binder clip.
N/A, but see the following: