A 1925 build might still be balloon framed, in which case, you may be required (here you would anyway) to fire rate (resilient channel, 5/8" fire-X drywall, non combustible insulation such as rock wool between floors and separating walls) external and load bearing walls in addition to ceilings and dividing walls. 

CO is actually a byproduct of combustion and is odorless (hence one of the reasons it's so dangerous) and that's what the detector is for, because one can unknowingly breath too much and it can be fatal.  

Mark my post Bryan Neal,In the next 4 years, you will realize that your 65/35 to stock/bond index buy and hold strategy will put you nearly where you started in the year 2000, right before the .com bust. 

The woodstove is installed correctly, with correct clearences to combustible materials (including the chimney setup)2.)

B-vent is useful if there is no chimney, because clearance to combustible parts of the structure can be minimized.

I plan to take it apart this summer and clean the burners (hack saw blade to the slots) and seal up any gaps in the cast iron puzzle pieces that comprise the combustion chamber (but first I will blow theatrical smoke inside the chamber in order to suss out where any potential leaks might be).

In order of decreasing importance, I worry about liability from burns on children/pets (they get ridiculously hot while operating), risk of house fire (like if they lean something combustible against it or do not provide a wide enough berth around it), and smoke damage/deposits on the walls from improper use/air mixture adjustment. 

Type X gypsum board is wallboard to which non-combustible fibers have been added.

You have a stove, and the backsplash there should be non-combustible ...

I'm not in the business of telling people how to live their lives, as long as it's not interfering with mine or hurting my investment.If he has things blocking the airflow, hiding water leaks, too close to combustibles, attracting mice or ants or roaches, bothering the neighbors . . . that's when I'll act.