The right lender will be able to advise you on what options you have after getting some info from you and taking an application. 

Pay for 2 hours consultation time from an attorney experienced in contractor real property law (if you don’t know of an attorney contact me and I will provide a referral) to understand the specific applicable laws, the risks, and potential costs2.

In some cases, exemptions or adjustments might apply for buyouts between co-owners, so it’s best to check directly with a local real estate attorney or tax advisor to confirm the exact tax amount and any applicable exemptions.

The standard to apply is quite simple: Did you accurately disclose the character of the down payment funds to the lender in the loan application?

Google search gives me these super wide ranges and mostly talking about adding a bedroom in a SFH, which I'm not sure if applicable to this situation of "moving/subtracting a bedroom from one unit and add it to another unit in a duplex". 

it's probably just a matter of casting a wider net in terms of applications. 

In most cases, they learn of the transaction only when a Certificate of Occupancy (CO) application or a permit is submitted for repairs or inspections. 3.

I'd like to know other landlords' experience of the application, placement, inspection, and renewal process

In this group, you get many exclusive benefits, including a discounted management fee rate of 9% on all properties managed by PPMG, plus the $250 application fee for new applications is waived.This property will be one of my highest cash-flowing properties.

What an agent with experience can help you with is the underwriting process of an applicant and drafting a lease.