OTH, if you are going to impose this on him with little interest on his part, don't do it.

You'll want to take into account all easements and build restrictions (in addition to zoning) that may be in play that would limit your ADU size or location. 

If she is m2m it could be now but I’d be careful with COVID restrictions.  

Are there any restrictions on large multifamily or setbacks that an out of state investor may not be familiar with in the area?

As mentioned, I've found a neighborhood in my market that'll support my house hack model (outside city limits, large lots, lower taxes, low restrictions). 

Would an exclusive agency agreement in any way restrict my ability to assign the property to another investor? 

Sometimes these deals take patience, and due to COVID eviction restrictions you need to be extra careful.

Plus waiting in line at Home Depot daily was a chore. we are under contract for another property on the west side, and I am not looking forward to trying to get this ready with all the current restrictions.  

Of course, I would need to check the HOA documents for other possible limitations imposed.

@Jake Fugman aside from the self-sufficiency test, are there any other restrictions that often trip up FHA financing?