As long as you're on the deed, you do not need permission from all parties to change your homeowners insurance if it is in your name. Anyone with a vested interest could also insure the property how they see fit. If you have any questions, don't hesitate to ask.
There is no straight-forward answer to what building materials you use for your house and the homeowners insurance rate you will end up with. Here's a tip to keep in mind that may help you make a decision: brick, stucco, and concrete are preferred by most insurers because they tend to be flame-retardant so the risk of losing the whole building decreases.
Unfortunately, if you start the claims process, the insurance company can list it on your CLUE report through LexisNexis which contains your claims history — even if there was no payout or resolution. You can dispute with State Farm to see if they will remove it, but at this point, that is really the only option which is definitely frustrating.
Insurance companies (depending on your policy and whether you have replacement cost value coverage) are obligated to bring your property back to its previous state, but no better. This, in theory, means that it should be no worse as well.
That depends on what parts of the property you are responsible for. If the townhouse shares walls and you are not responsible for the outside of the property but own the townhouse (like a condominium) then you qualify for an HO6.