Just curious why a certified letter would help? 

My question is; is it better to not ask the seller to pay for the buyer agent's commission (not include it in the offer letter) so that I pay it by myself and get a tax write off on this commission expense for the ADU's sqft portion?

Property Details- Size: 64,000 SF Class A mixed-use building - Commercial Space: 25,000 SF - Residential Space: 39,000 SF (32 duplex apartments, 2BD/2BA) - Parking: 165 spaces Vacancy and Rental Status35% of the prime commercial space (about 10,000 SF) was vacant and not marketed for rent online. 13 of the 32 duplex apartments were rented at 35% discount to comps What made you interested in investing in this type of deal?

I also think sometimes would I want to live around a bunch of old people or would I thrive more from being around a mix?

Buyer letters were great too until they did away with those. 

Ask for a "Pre-Underwrite" this is where the bank underwrites the file and give you a "Loan Commitment" instead of a generic "Pre-approval" letter.

@Katharina Bormann in my experience they don't like those official looking letters in the mail so make sure you do that and also have a cost associated with unresolved issues like trash in your lease. 

letters.

@Jae Yoo you have a few options:1) Hire an attorney to write a threatening letter.