The rentals are scarce and rents have increased in recent years.

I recommend you do this annually to adjust for utility increases and other variables.

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.

With high home prices, rising mortgage rates, and intense market competition, securing a property has become increasingly difficult.A recent survey found that over 60% of real estate agents reported instances where Gen Z buyers lost out on homes due to delayed decision-making, missed appointments, or hesitation in making offers.

The shorter the prepayment term has an impact on increasing the rate.4.

I do not understand your remark as related to the DSCR loan.  2 ADUs are not allowed by f/f conventional financing but is not always enforced.Fortunately if you stay with the current tenant without a refi, by the time you pay principle it is likely the rent will have increased enough to absorb the increase mortgage payment. 

The use of the accelerated depreciation strategy helps real estate investors to reduce the tax liability immediately which therefore increases their bottom line due to the offsetting of income.

Do you see any new rental property up in the market has increased rent since L.A. fire issue?

The reason I say this is that with a 5+ unit a lender will evaluate based on NOI and a cap rate, so adding a 5th unit COULD (or could not) substantially increase the value of the building and make it worthwhile to refinance and pay off the existing loan (that is tied to the "old" quad) anyway.

But, insurance costs are likely to rise, making getting mortgages for most people even harder to get.What is likely to happen is more creative financing going forward, private lending to increase and smaller houses being built in the future.