For example, if the 3rd unit has been there for a long time, your best argument may be to contend that the 3rd unit should be “grandfathered in”.As an alternative, consider expanding the 1st floor unit into the lower level.

Though I have seen it alternately praised and denounced, the simplest for me to wrap my head around is to take the average local rents, multiply by 2 (for duplex, obviously..), divide in half and subtract the mortgage rates.

The alternative after all that is to buy using a portfolio loan.

They will invite all the neighbors to a hearing about it and if there are any objections, they will deny your variance.An alternative to this that I have commonly seen is condominiumization where the land the home on is declared common to the association you create and then each house is deeded separately.

there were 3 alternatives for longer terms for less of an increase in rent.

I don't know (recall) if they are in local ordinances but I do recall vaguely seeing some legal / ordinance type of material detailing when it can and cannot be done, regarding building in a way that directs water towards a neigbors property.I don't know Chicago that well, but as a homeowner I would try calling your local building and permit center and see if one of the local inspectors can direct you to the code section to read.I'd do that before anything else because knowledge of those ordinances will arm you / prepare you best to approach the other parties.With regards to the possibility of 'dealing' with the water, I'd be thinking about ways to do that, too - in the event that the above / negotiating an alternative solution is not fruitful. 

The alternative is that interest rates do finally begin to rise, which puts pressure on all of the companies that are overleveraged.

What are my options or alternatives?

I agree there is only a subset of estates where this might work; it will not where the heirs are unwilling to wait, if there is significant debt, etc.I am not interested in deals where I have to acquire the property outright; I am trying to come up with an alternative method.

Oh, and the "criminal" complaint appears to have been pretty lightweight - I just had to pay a $95 fine.