I cannot afford another above the $16,000 which is why I told her $15,000 was the budget.I also stated to let me know of any extra charges that come up so I can watch the number.

In the case mortgage foreclosure, I usually offer to pay for the existing mortgage and give them a little extra to move.

And that extra $40-$50k a year will be life changing.

Sometimes you might want to go extra on something like the master bath or contemplate other exit strategies.

Adding mass to the walls works wonders—attach Mass Loaded Vinyl (MLV) to the shared wall, then cover it with a layer of 5/8” drywall using Green Glue soundproofing compound for extra noise-blocking power.

Should I take extra steps to verify their identity and legitimacy?

It may sound nice to pay a 6% management fee but the extra fees can add up to be more than the other company that charges 10% with no additional fees.

(You say it’s worth about $100k more than you’re paying so figure an extra $15k.)Maybe you’d be better off partnering with the parents unless they have zero interest?

then theirs charges 1000s in extra fees. 

Quote from @Caleb Brown: Someone else asked but what would market rents be including the extra storage?