I just brought a 2 unit property with one existing tenant.

I would be concerned about the slope of the line to the street when they replaced it.If the slope isn't right or they have funky bends in it to go around big roots or above them that's when water and debris can sit and cause constant clogs.About every 3 to 6 months the plumber then has to come out and scope the clean out outside to unblock.If material is with dirt etc. is back up in the toilets or they slow drain or make a gurgling noise with bubbles you could have an issue.Make sure as mentioned before buying you get a plumber to scope it out all the way from the toilets to the main and the street to make sure there is not any issues with slopes or clogs.I have heard many horror stories where a buyer calls the county or city and they say on the phone that everything is fine and after they buy it they get hit with all these costs,fines,etc.If they won't give you something in writing I wouldn't feel comfortable about it but that's just me.So this was an existing line to the street and not a sewer tank that they converted later and hooked to the city or county correct??

How do I get a handle on these numbers beforehand without an already existing loan?

If that exists, you can be confident that both of you will work equally hard to ensure success.

The general rules of endorsing note are function of UCC regulation see § 1303.25.

But that brings another line of thinking: best entity for flipping - there is already an existing BP thread on this matter.

Building lots are a tough sell these days because buying an existing house is almost always cheaper than building.

No rules should exist.

"they are good at giving reasons why they should be paid upfront something however (usually they tell us in will increase chances)"They are full of crap.Buyers are hungry for real lenders who can perform.If you are a mortgage broker with real lenders you will make plenty at closing.If people are looking for 100% loans and all this other type of exotic stuff it really doesn't exist unless you have a property worth say 2 million that you can get for 1 million but even then you have points and closing costs.It's all a pipe dream and buyers need to not fall for the scammers traps.They know these buyers are wanting to buy into a large deal above their means and "hit it big".They suck out the 10k to 15 they have or more selling a dream and then do not fund.

Ellen Bouton, Kim Knox is right, you need to go through your existing contract and see if there are restrictions on selling w/o paying it off, or with paying it off.