If your PM is not communicating with you on a regular basis about the status of the property's activity and also not responding to your inquiries in a timely manner, that's a problem.

No, material costs sit nearly identical.

For a regular residential deal you can expect a 5-10% contact rate on any list you call.

You can pay for it with FHA loans or regular loans.

Who will drive by regularly and check for unauthorized renters, weeds in the driveway, trash piled up, a tenant taking up five parking spaces, or other issues?

If you provide seller financing, make sure you are a named insured on the insurance certificate like a regular bank. 

I regularly listen to the bigger pockets rookie podcast.

As I got to know more investors, I learned many of them were regular people that worked hard, saved up, and invested.

The CMA is right on the sale price - My payments to the seller includes a 25 year amoritization rate, so my monthly "mortgage" to the seller(300k with interest) is greater than their current mortgage. (200k with the same interest rate)- Going the regular financing route (25% down) is not desirable since I would need to dip into my primary residence HELOC for the downpayment.

So far as actual days of the week, Mondays can be busy with regular operational items, weekly reports, weekend follow-up, etc but generally speaking Friday is much busier than Monday because teams are getting ready for weekend move-ins and more people come to see apartments Friday/Saturday than any other day of the week.