The insurance companies are allowed to raise rates by zip code not on an individual policy for “an act of God” claim.

The scale of your development (large scale apartment complex or individual singe family housing) will determine the method that you would use to locate any utilities. 

You may want to checkout magic plan which allows you to virtually scan a room and create a floor plan and estimate material quantities.https://www.magicplan.app/estimates/

You may create a holding LLC in WY or NV that will own all these sub LLC.

What strategies are these individuals using that make them so successful?

Create a relationship through emails, letters, and Phone Calls, and you will see results.I have sellers calling me that I first spoke to over a year ago!

QuestionIf I want to Invest In the boomIng parts of the country and have a trustworthy national lender that I work with, what are:-strategies to find good cap rate multiplex properties (2-4 unit) -other things I need to consider if I already know I’m using a property manager (and wIll always see sIght before offerIng) -some success stories from individuals who invested from a great distance (in country) Thanks!

I’ve found being in a mastermind of like minded individuals helps me excel more as everyone in the group encourages and wants me to succeed. 

More cost effective than setting up individual LLC's for each property.

Yes, assuming you've created 2 separate units it's usually a zoning violation at the least.