If that won't work, there's a slip-in flange that has a rubber gasket on it that seals it to the existing pipe - I've used these on cast iron before.

Or is this something that can be done with an existing LLC? 

They depend on the actual demand that exist. 

Instead of buying fee simple, you're buying sub2 existing liens. 

You may get better tenant retention if: (1) the tenants are paying utilities; and (2) the existing windows are so old that it barely insulates.

If there's an existing lease, it's binding.

If you can buy an existing duplex for $100k, but it will cost $200k  to buy the lot and build a duplex, then it makes no sense to build a new one and therefore the lot is worth very little.

And it is those results that lead to 65+% of our annual property sales to go to existing clients building their existing portfolios. 

Partnership opportunities that exist?

If you can't find the leak after confirming it exists, call in a good plumber.