1. Suggest you post your list of schools and get feedback on each. I'm not sure if there are any really "good" ones but there are certainly ones to avoid.
2. Correct. Only SAA in San Diego, HAA near Portland OR, and a few schools in Florida (
AFAIK) have F-1 approval. I believe there is a list on the DHS website.
3. I did about 750hrs in a year without trying very hard. A contemporary of mine hustled and did about 1200. Pay was OK before the virus - $40k a year or so, enough to scrape by on. This may no longer be the case.
4. Good question. I think quite a few of the delays were due to flight schools being overrun with students and not having enough aircraft / instructors. Examiner availability was an issue too. These factors may have improved in the post-virus world. Ballpark, if you work hard and have all the resources (aircraft, instructors, examiners, weather) you can go from PPL to MEI in about a year, but safer to plan on 18 months.