It might be the way I have to keep going but it's why I'm exploring this fund option as an alternative.1.

That said, I'm grateful for the alternatives you present--you're keeping the bottom line in mind, so I appreciate your help in exploring options that achieve the bottom line for the investors. 

. - that might be a situation where you would want to work with a contractor directly because you would have lots of different options with widely varying costs.

You should fire them right away and talk to an attorney to prevent the loss, but I wouldn't expect much and it could be a waste since a company that does this will not have the money to do anything.When you have just one unit and you are looking for PM companies, your options are the bottom of the barrel because it's not a good use of the big one's time.

This will show you that people have options to go out and pick another house over your place. 

I have 2 options:- finance the construction pre-selling the apt, and take my profits (expected to be around 700K pre-tax); or- finance the construction with a 6-7%/year loan (collateral = my house), keep the 10 units, and once the building is completed in 24 months, rent them for circa 180K/ year gross.

Honestly, I would not sign any lease until you positively close and legally own the property.

I have first hand experience as an investor which has been positive. 

Most 1-4 unit real estate investors are using DSCR loans right now for any buy and holds while flippers lean on higher leverage bridge/fix and flip loan options with higher interest rates.

And use all of the proceeds from the sale in your purchases you'll defer all tax.This does give you some interesting options because you can allocate those proceeds anyway you want.