Character name: Greg House, Art Mullen
Will your character be able to sense Hawke's magic/presence? Nope, neither one of them.
Could Hawke’s equipment affect (or not affect) your character in any special way, whether because they’re a demon, undead, or some other reason? Don't think so.
Could Hawke’s spells affect (or not affect) your character in any special way, for whatever reason? Neither has any special abilities/powers so no
If your character is a demon, do you think they would be able to affect Hawke on a mental/magical level, if not through outright possession? If so, how would they be able to affect him and to what degree?
Is there anything Hawke may be able to sense about your character given his magical connection to the city? Art and House are both plain old humans so...no?
What, if anything, may he be able to sense about your character regarding the city's influence or degree of connection? House has been to hell and interacted with a number of powerful beings (Eve, God, Malek) I would imagine Hell, at least, would've left some kind of impression on him that someone magical might sense.
Is your character affected by anything that may block his ability to sense city connections? Nope, neither
Anything else I missed?