it depends on local authority.. MBSA wouldn't be surprised if consider 20'. Technically we measure setback from the middle of the road. They usually tell end user 10/20' setback from boundary as a guide to simplify.

from experience the red highlighted area is non load bearing and not a shear wall. load bearing tend to be 10 to 20 ft span and dont go into a corner like that unless it is a lift shaft. i think the 3-5k is security deposit that is refundable unless your renovation cause problem to others. mgmt usually brush off cos they dont know about design and best to avoid committing. you need to submit your own drawing and they forward to the original archi/engineer for approval and usually got fee involved just to pass these documents. Bear in mind you can dont inform and if all goes well nothing wrong. If things go south you will be breaking a few of their covenant of agreement signed when taking possession of unit and can be sued.

not a sifu. what you experiencing is bureaucracy. nobody wants to be responsible if something goes wrong. best to err on side of caution and bs that cannot hack. most ppl would be put off by this. even though you can prove to them do you think they care?
that being said sometimes we use these brickwall as added protection as stiffeners for slab deflection control such as the big span in your living room. on such a small room where there is close support btw span, not that important. the caveat is most of the time brickwall are non structural, but on rare instances there are exception to this, so dont go on assume just becos brickwall non load bearing. my comment is only valid on this case on this plan. true you can do what you like on your unit but it also depends on what agreement you signed with the developer on taking possession on that unit and all their regulations. my advice, no need make a big fuss, get your contractor in do their job and just leave it.