I am working on forming a possible partnership with someone who owns multiple lots (lots are SFH up to 16-unit apartments).  I have the construction contacts and access to funds for the ground up construction (1 build...

Having no money is a indication you are not able to properly manage your finances.

So why do theses HVAC contractors charging more than 8k for parts and installation?

As above, I plan to install storm windows now (in the spring-summer time) to cut costs in the winter.

I would install a 2nd meter and have tenants pay the water.

My understanding is that the HOA is responsible for maintaining the retainer wall, but I wouldn't want to be out of luck should a snow storm or heavy rain damage break it down.My Real Estate Agent is assuring me that this isn't a problem as it's been professionally installed and the other neighbors have been living with the same retainer wall too.What has your experience been with a retainer wall?

If it was done properly the Optionee (tenant buyer) has the exclusive right to buy, so you'd have to purchase the right from them.Sounds like a mess.

And if used, how much does it cost to properly get rid of it ?

When writing a contract you will have dates and deadlines that you can get out of a contract with proper reasoning.  

The fact they are complaining online might be an indication the property manager dealt with them properly so be sure to ask the manager for their side of the story.7.