(we have experience with painting and bathroom/kitchen demo)Any advice would be greatly appreciated!

I have demoed alot of the names you mentioned and like rent manager with yardi a close second... we are in california so labor cost is a concern with a traditional excel/quickbooks approach as well as potential legal problems with the possibility of mistakes that you mentioned.

Other than that, you can only know what's behind the wall when the demo is done.You buy your ticket and take your chances. 

Most reps will give you this info in exchange for a demo with them. 

Usually, I take all the demo materials to our local transfer station.

If building can't be converted then have to build in demo costs to get to a clean slate again.No legal advice given.

The demo and trash out saves money and it's a fun workout. 

The house is filled with garbage, needs a complete rehab of the kitchen, baths, flooring, exterior paint, landscaping, roof and mechanicals but he demoed most of it already.

I then do a detailed analysis of the area (demo, rental velocity, pricing etc) to further solidify if the area is a good place to invest in. 

This BRRR will have minor reno with demo starting this weekend in the bathrooms, electrician taking a look at panels (precautionary step), flooring, trim, spackel and paint Monday.