If they don't, give them a 7-day non-curable.

Understanding their cash flow is critical.I especially like your idea of communication clauses—non-responsiveness is a huge red flag, and setting expectations upfront can save a lot of headaches later.

It depends on the lender but at a min they must follow TX SML or lending laws in the state in order to compliantly lend in TX, on whether choose to apply this guideline to all types of occupancies or transaction types (non owner investment, second homes/primary residences, etc)80-85LTV on rental properties is only on the purchase for fannie/freddie loans but on rate term refinances its max 80% and cash out max 75% for 1 unit and up to 70% for 2-4 unit cash out conventional.On HELOC's and rentals are up to 70-75% depending on the HELOC investor or product.Its good to distinguish between what the lenders are willing to do and for which product and also these loan products must abide my state law as well as an additiona layer of "overlays," on top as well (whichever is worst / most conservative).

Rent out part of the space at least to help pay for mortgage and utilities.  

I read some old posts where folks have suggested using non locking door knobs is that something tenants like ?

There is a contract that is signed.These are "quick" transactions, within days, that the borrower (Subto student) needs "immediately" to provide a non refundable emd, for a Subto transaction.

These loans are not allowed in non-owner occupied scenarios. 

It explains why very few flippers are adding single ADUs and if they are they are usually a conversion of exhisting habitual space (bunk houses, detached offices, workshops, craft rooms, etc.  

There are plenty of cash-flowing markets here - especially in the STR space.

I can imagine that, with the wrong mindset, it could feel like an invasion or disrespect of your personal space.