Probably more uncommon than not, but something we do come across frequently.  

If your 12 lots were legal lots of record prior to the Zone Change and General Plan Amendment the City HAS to let you build on them or can be subjected to a lawsuit under the takings rule.

Yes, wood siding is more subject to moisture damage and rot, but you can pretty easily cut out a section yourself and (hopefully) replace it with an exact match.

Coker II, I can only answer 5 and 6; 5 - BP Podcasts and books are great topics on the subject.

I wrote a pretty lengthy article on this subject (and how to avoid it) that you can find HERE. 

If the sale was by a quit claim deed, or almost any other deed other than warranty deed, then depending on if any other documents were signed by seller regarding liability for “back taxes” he may not be responsible.Since as to the taxing authority the taxes stay with the property, if you or someone doesn’t pay them, and assuming no mistake was made as to their status, then your property is subject to any and all relief available to the taxing authority, including lawsuit, lien, or foreclosure action.

Since it appears your friend knew there was someone in possession at the time of closing and agree to title take subject to that possession, even though the Insured was mistaken as to when that right to possession would end, there may not be coverage.. 

., notes subject to certain banking regulations).Again, consult an attorney.

Who does subject to, seller finance, and/or lease options in Dayton or surrounding areas?

We agreed subject to inspection and them removing the lower unit tenants so we could live there.