The customer service level reflects the difference between indifferent salaried people checking boxes and letting automated software do whatever it wants to do, and folks paid for production (like if you went the refinance route, rather than assumption).

Will they expect more down?

Just that learning experience is worth the $100 the first few that come out more than you expect.

Even if you find the right deal and secure the right funding, you might run into property management issues.Your investors (15-20% CoC) have unrealistic expectations.

are these cash buyers expecting calls from strangers like this?

If you have a high enough salary you might be able to buy a small multi- 2 to 4 units, and house hack - living in one unit and then renting out the others. 

That being said you each hired someone to give an opinion, trust in your guy, but don't expect them to trust your guy over their own expert.

He has no idea what he is doing, he has no experience and no capital - but he expects to make a fat profit on his first deal.

If it's a bank or other institutional lender (a company whose business is lending), you should expect they are plugged into the credit bureaus and will report your payment history there.If your lender is a private person, like a friend or family member, or maybe a local person who makes a few loans a year, I would assume they are not plugged into the credit bureaus and the loan won't show up on your credit report.Keep in mind that if you apply for other loans, and they ask you for a schedule of real estate owned and mortgages you're responsible for, and you omit a property and/or private mortgage from that listing, you'll likely have committed fraud by saying that you're submitting complete information about your financial situation but intentionally omitting something.In other words, a loan/property may not show up on your credit report, which means a lender you're applying to for a mortgage may not know about it, but that doesn't mean you're not required in the application process to list it anyway, and it does mean that if you intentionally omit it, you're probably committing fraud or breaking some other law(s).I would assume that the loan could show up on your credit report, and that you will be listing it in future loan applications to institutional lenders, and behave accordingly.

I’ve been researching and looking for a while and was fully expecting to look at a bunch of properties and it being a while before I found one that was perfect and I think I might’ve with this one.