Just some notes to consider based on what your unit is like. 

Not sure how many PMCs you've had bad experiences with, but we'll take exception to:"Then do a thorough research on tenant applicants (note: leaving this to a PM may be hazardous to your financial health)".BP seems to have more threads about screening mistakes by DIY landlords as opposed to PMCs.Now, if you'd have mentioned Maintenance, you'd get no argument from me:) Even the PMC industry acknowledges maintenance as one of the biggest challenges.Rereading my post, I kinda see how I sounded negative toward PMs.  

One thing to note- the building is older (built in 1922), is considered in a historical district, and although each unit has been fully renovated, I have not upgraded all the electrical/roof and plumbing, so that's on the older side which I know is more challenging to get insured... 

Also, if you have a below market interest note, if you wanted to sell that note for any reason in the future for liquidity you would be affecting the value of that note negatively.

If Im understanding correctly, youre buying the home from your mom who will take a first position lien on the property in exchange for carrying the $100k of the purchase price on a private note.

I have bought sold either properties or notes in about 30 states.  

If you do have to show tax returns, it will show your LLC owns a property and you can show underwriting a copy of the note to show that you are not liable for this mortgage/note.

One thing to note when getting conventional mortgages and spouses.There is a 10 limit per person for conventional financing.You can either do 10 conventional in each person's name which would be 20 mortgages for 2 people or if you do the mortgages jointly, will only allow 10 in total.My thoughts are not to own joint assets until you are both married. 

Note that RedFin shows Y/Y January 2025 price declines of 9.71% for all housing but increases of 2.8% in single-family homes.

Sellers can avoid paying transfer taxes to the county, while buyers are spared from facing significant property tax increases.However, it's important to note that lenders typically only approve these loans for properties with five or more units.