On the issue of whether it's a good idea  ...

Regarding the secondary roof issue, your first step should be to consult with your current insurance provider.

I'd look over the rental laws before deciding if you want to rent your home in CA or buy a rental in WA. 

Andrew, you bring up some very real and raw issues regarding REI that many don't talk about. 

That sounds like a pretty good plan, but I would make a few suggestions:1) if you think it may have had squatters or the previous residents would come back, board up the windows too while you're doing the work. 2) If the property was occupied by the owners or tenants, you may need to file an abandonment notice and wait 10 days or so (check your local laws) before changing the locks. 

Sure you need bedrooms and bathrooms (with 6 bedrooms make sure your house septic is adequate according to your Township laws about occupancy limits) but in order to get booked compared to other houses, you need to look Instagram ready.

Also as per WA state law landlords must list screening criteria. https://apps.leg.wa.gov/rcw/default.aspx?

While they have a right to be present, they can sabotage the showing, talking about their issues with other tenants or neighbors, wasting everyone’s time.

What I would do is politely communicate the issue to the applicant.

Ultimately, if anyone is unable to obtain desired financing when their property is owned as an LLC, its the guarantor that's the issue and not the LLC and suspect the guarantor would have the same struggles regardless of whether the property is owned as an LLC or in their personal name.