There is a big difference between evidence needed when applying under the 3 year rule or 5 year rule.
N-400, Instructions for Application for Naturalization (uscis.gov)
Your first I-130 is DOA.....send USCIS a letter, using the receipt number, to withdraw it. Then, refile a new I-130 with evidence of meeting after marriage ceremony.
90 day rule is a Department of State guideline....not a USCIS directive. I cannot recall anyone ever being denied due to this "rule". The USCIS officer won't even ask you about it.
Apples and oranges. This was a business deal in which both the borrower and lenders were happy. Valuation is subjective..... James campaigned on getting Trump. This is nothing more than a political hit job by haters.
There is no 90 day rule. You can marry, get the marriage certificate, then file the I-130, I-130a, I-485, I-131, and I-765 right away.
Be aware of the travel and work restrictions when filing to Adjust Status.
Sounds like no I-407 was signed. Therefore, he is still a legal resident. I don't think the officer handled this correctly. Personally, I would file the I-90 online immediately. I don't understand why he would have to leave the US.
There is no USCIS field office in London.