Although I hold a brokers license and have for 45 years, I operate exclusively in the commercial arena.  

Problem is that the insurance policies have too many exclusions and opportunities to avoid you being covered.  

But, excel is totally fine in the beginning.We use QuickBooks Online exclusively for all of our REI Clients.

These two things aren't mutually exclusive.

We’ve flipped homes and now exclusively lend on them in Los Angeles.

Fannie Mae's guidelines verbatim are as follows:Must be occupied by the borrower for some portion of the yearMust be suitable for year round occupancyBorrower must have exclusive control over the propertyMust not be rental property or a timeshare arrangement (this has the following disclaimer in the guidelines:  If the lender identifies rental income from the property, the loan is eligible for delivery as a second home as long as the income is not used for qualifying purposes, and all other requirements for second homes are met (including the occupancy requirement above).Cannot be subject to any agreements that give a management firm control over the OCCUPANCY of the propertyThis means that as long as you intend to occupy the property some portion of the year, you could absolutely rent it while you are not using it. 

I worked for Marcus & Millichap in their Capital Markets (Mortgage Lending) business and he worked with us exclusively.

Creating an LLC in NY is a hassle - all sorts of nonsense about publishing in newspapers for 6 weeks, etc.I tried to research what it would take to own and operate a rental property in NY with a different state LLC. 

When I started in the STR industry I used exclusively nest thermostats and could never get them to lock temps when in dual temperature heat/cool mode.  

My overall portfolio yield (exclusive of appreciation of real property of note discount at purchase) is about 14 - 15% annually.