Readers should seek professional advice.

I've been corresponding with a non profit in CA that is doing work on ADU regulations, etc.

Readers should seek professional advice.

If you control how they perform tasks, set their hours, or provide tools, they should likely be a W-2 employee, requiring you to withhold taxes and comply with payroll regulations.

@Daniel MadhavapallilYou should hire a tax professional. 

Technically, when raising funds under Regulation D or any other SEC exemption, there’s no strict requirement to utilize a Private Placement Memorandum (PPM).

SignaturesThis Agreement is binding upon the parties and their successors.Contractor Signature:[Printed Name] [Date]Subcontractor Signature:[Printed Name] [Date]AttachmentsScope of Work document.Project drawings/plans.Proof of insurance and licenses.Payment schedule.Note: This template is for informational purposes only and should be reviewed by a legal professional to ensure compliance with local laws and regulations.

Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Assuming they are professional and skilled in the craft - alot of the issues you have faced, they will remediate and mitigate moving forward.

Companies tend to do well when they professionally respond to negative posts, and either provide their version of events and stand their ground, or do what it takes to turn the angry poster into an ally.