We are currently living in one side renovating the kitchen and basement at the same time.

Is the rotten wood under a kitchen or bath, or near an exterior wall?

I've been getting prices from local extended stay hotels with kitchens.

Same as many tubs and kitchen sinks. 

We will have to do some renovations (kitchen, flooring, paint, etc) and we are talking with a few contractors in the area now.

Two concerns with it:  1. not sure if I can expect to be able to refinance with 80-75% LTV on the after-repair value  2. inefficiencies likely to arise replacing plaster with insulation+drywall and installing super basic kitchen, when ultimate plan is to replace floors and put in a nice kitchen. 

(No warranty on existing equipment).

Also, if you have shared spaces such a kitchen, you will need to have rules and decide how you are going to manage the cleaning etc. 

The water heater is on its way out.What are the rules for taking de diminimis for a piece of equipment that also offers a tax credit?

I felt by managing myself, I would be better equipped to manager my pm, since I had experienced many things by managing myself.