Your powers of observation are legitimate enough, in my opinion.If your friend saw mail in a way that wasn't illegal, he could be a witness.  

If a legitimate broker has a good deal and can take a 5% commission why would he want to take a $500 finders fee from some shady out-of-state operator they dnn't know?

They do the paperwork at a kitchen table, don't buy any title insurance and record the documents themselves (entirely legitimate, but a title company will ensure things are done properly.)

All 3 companies listed here are legitimate funding sources, but the market is fluid and so are guidelines, Khiavi valuation process can be tricky, but they try to utilize inhouse resources to help with speed. 

I just want to know if they're a legitimate business and I won't be the victim of identity theft or the like.

And remember that regardless of what you may read on the internet - you will be responsible for all transactions in your IRA.There are many legitimate ways to invest your IRA funds without bringing disqualified person into transaction.

Good data means true repair estimates and legitimate ARV estimates.

Who’s gunna ensure the comps are legitimate? 

It's people like her that are operating illegal short-term rentals that are creating this backlash against them and making it harder for others to operate a legitimate business. 

I'm glad you prefer to do it that way anyway, but keep in mind it's not about preference, its important so your LLC remains legitimate in the eyes of the courts and you will retain your liability protection.