Looking to supplement retirement-he's retired and I'm still working full time for next 2-5 yrs.  

I would start with BP like you did, supplemented by simple Google searches.

@Zeke ListonLancasterI have a generic one but would like to get something with more meat.

Can I have (5) of them sign a generic "investor agreement"?

When you send a rejection letter do you say why or just have that generic "Adverse Tenant Reaction" letter and checkbox something on the list like "past judgements"?

My first major goal is to provide enough income to supplement what I make at work. 

He insisted an operating agreement online would not hold up and would not provide me the full legal protection of an LLC (quite generic).

I'm sure this will add significant cost either way.Long term I'd like for my parents to be able to keep the DADU as a rental and supplement their income as the rent would likely far exceed the loan payment since they are located in a HCOL area (Redmond, WA).

With the second ADU will you go for a more generic layout so it can be somewhat reusable, or is every lot/build unique?

Fewer people are fooled by the generic “proof of funds” letters that used to be available from hard money lenders.