Thanks for this post Joshua. I think pursuing REI goals and being on board with a spouse is something that a lot of us have to think through here. Its good that you're asking this. Gaining clarity - would you still be house hacking and have a property manager?
This is just my take, but there shouldn't be a 'but' after a thought of your wife being in danger in a neighborhood. I think she has a legitimate concern (if I understand the scenario correctly).
I definitely see the value in house hacking in general, but I question whether the overall value is worth it considering the stress and difficulty it could put your wife (and, indirectly, you) through. Not sure what type of multifamily this is, but in general you're living next to much different people in these sorts of buildings - different than say conventional SFRs. That could not desirable in a rough neighborhood (even if it's up and coming). Think about what it might be like for her as a mother: will the baby have health problems from the dust created by your neighbors smoking outside of their window, or from dust from renovation work, or mold in the house that you're having to treat? Will the baby sleep if there are neighbors fighting next door (or above...or below)? What if she's having to go up and down stairs all the time with a baby in her arms (I did this and it's not fun).
I'm not at all trying to deflate a viable dream toward successful investing, but when it comes to marital success and real estate success I would encourage you to think how those two things can be done together instead of how you can bring your wife on board with your goals. What are her goals and dreams? How can hers intersect with yours?
I know this is said often, but it's very true: happy wife, happy life. What good would investing in a MF property be if your wife will be miserable?
Maybe there are other paths you could both be taking together in this? The beauty of real estate is that there are many diverse ways to seize opportunity and build wealth.