What level of remodeling did you complete and do you care if it gets destroyed by tenants?

Before it was rented I added kitchen cabinets and a counter where there was none, remodeled the bathroom (not a complete makeover, but substantial), added a dishwasher and installed flooring.  

I'm an admitted over remodeler, working on that.

Check out some other options before you signs the deal.When I was getting quotes, I compared a lot of bathroom remodel companies on this site.

You could have found a nice one to remodel and continue the profitable venture. 

Would it be fair to offer the price the owner was asking before this most recent unfortunate remodel?  

There will be this trade off that you will get out of any remodel. 

My mortgage is very low and I have just remodeled the kitchen and remaining upgrades will cost less than $5k.

I'm thinking with about 50k invested in remodeling, would bring the rent to approx $1500-2500/month for commercial space + $1500 for the residential = approx 3.5 k total/month.

But when you go to sell your flip after the remodel then you negotiate the commission with an agent what you will pay them at closing, as well as, to any buyers agent that bring fort a buyer.