If you plan on going into the commercial arena, you need capital and experience.

you can find good trained and certified inspectors from association itself https://www.nachi.org/certified-inspectorsand ASHI

But that would obviously not work with a syndication that you were looking to invest in the near future.Also, keep in mind that syndicated deals are also leveraged, so if you are set on going this path, a syndication that uses 75% financing would be like financing 94% of your purchase, using your 25% down scenario described above (not 20%). 

These are professionals with additional training and a stricter code of ethics.

Hire a solid bookkeeper as a contractor for ongoing bookkeeping support to handle the day to day grunt-work in your books.

At some point, you're going to pay for a mastermind, training, or a coach and that's all trial and error like the rest life.

The local spa services charges over $300 to drain the refill, but we trained our cleaner on how to do this and she only charges $100. 

You will just quit your W2 job and become a self employed property manager.So if you are looking for retirement income you should factor in the cost of a property manager, as well as turns, vacancy, repairs, and Cap Ex, which will probably alter the numbers you are expecting.Also add into this, personal asset protection set up and ongoing costs, as well as accounting advice, bookeeping costs, and tax preparation costs if you intend to go in that direction, and not do it yourself (which if you DIY will make you a part time tax repairer and also not retired).Many people get into this because they want to retire, but in reality it seems they are just quiting their job to become self employed.

A lot of big ones like Keller Williams have very extensive training programs that will help you out.

Wholesaling needs boots on the ground- if not yours, then someone whom you trust or have trained in your due diligence systems.