I also need a plumber and need to have windows replaced.

A plumber would have to snake a camera through the sewer pipes.

If not, you can have tradesmen (plumbers, HVAC, electricians) do work and pull permits and have handymen/carpenters do the rest.Whats the scope of your work?

Why look for a partnership when you could invest capital into one of many reputable syndicators? 

In the mean time i will get a plumber, electrician and the GC to get some estimates to see if my #'s are correct. 

Any reputable investor-focused agent should be able to quickly give you an opinion of value and whether or not it would be worth it to further invest in the property or sell "as is". 

Get a plumber to look at them and give you an idea if they even need replaced and if so how much.

Since you're saying the work includes both "lumber" and "pipe", I'm guessing this is a general contractor and not just a framer or a plumber?

Obviously I don't want to lose my own funds but I am in this for the long run and my reputation (based on integrity, experience, network, etc.) is more important than the money itself. 

Further, the gas tankless water heaters require to have a vent, depending on the location, it may add to the overall price of the installation.I do have a couple of plumbers who do install tankless water heaters.