The advantage of cash is that there is no financing stipulation, you can close much faster, and it is a more guaranteed sale.

Now, if your agreement was contingent upon your satisfactory review of all current leases, and that contingency has not yet expired, that becomes a different story (still pushing it if all of the leases are the same but you only want one tenant removed, but at least better than using the inspection contingency to add this stipulation).

The lease that you have with the carrier should already stipulate what happens if the building is demolished or the roof needs to be redone.

If so, how long and what other Stipulations do they come with? 

I agree, just do a standard offer and stipulate it's subject to the existing financing.

We had to stipulate in the purchase agreement that he was to stop all work immediately because he was "remodeling" one of the units and ripped out a load bearing wall to open up the kitchen to the living room.

Normally the settlement agreement would stipulate something like: you and/or the seller pay a much reduced amount of fines (I think on one occasion it was agreed a > $500,000 fine would be reduced to $20,000) to the city and the city will drop the outstanding violation, in exchange you agree that you will actually remedy the violation(s) within a certain amount of time (apply for the appropriate permits and so on).If you are confident that you can negotiate with the city and resolve it that way, it may be logistically easier to buy the house with the violations, and then resolve them aftewards (my first point)... but it's obviously MUCH safer for you to come to a binding agreement with the city prior to closing (that stipulates that the city gets paid for whatever they agreed to accept for the violations right after closing).

Definition I found online - A due-on-sale clause is a clause in a loan or promissory note that stipulates that the full balance of the loan may be called due (repaid in full) upon sale or transfer of ownership of the property used to secure the note.

I know there was something like this in Detroit, but I don't recall hearing about stipulations for the buyers. 

Its one of the stipulations that the credit union gave for the FHA loan I'm quoted for.