Exterior wall very close to neighbor's garage

[Chris May]

I'm looking into buying a duplex, but one of the units has a 10 foot stretch of wall that is very close to a garage on the neighboring property (less than a foot of clearance). I'm concerned about how to maintain the exterior over time such as patching the stucco and painting. There is also substantial buildup of plant debris between the two buildings so who knows what we'll find if/when we could clear it out.

I'm planning on doing a BRRRR house hack and the unit adjacent to the garage needs substantial renovations. The kitchen and bathroom are along this wall and they both need to be completely gutted and redone.

My questions are:

1. How concerned should I be about this wall?
2. If we're gutting the interior side of that wall anyway, should we consider replacing the entire 10 foot section of wall with something more long lasting? If so, what? Brick? We're in California so I'm not sure what the earthquake implications would be or if it's even allowed.

Thanks.