If you have a credit card with a high limit or a line of credit on the existing duplex that might give you some wiggle room.

Cozy has been acquired by apartments.com, and will not let me sign up for cozy, and the functions seem limited.

It's on a very small lot, with very limited parking for any kind of venue.

If you buy in a city with limited appreciation, every investment dollar must come from your savings.

More Buyers, Less CompetitionWholesaling relies on a limited pool of cash buyers.

SFR with ADU is no problem. but if you're considering adding an ADU to a multifamily property, consider the limitations you're creating on your back-end buyer if you decide to sell, or your own financing if you choose to refi. 

I have learned that in today's world of information you do not need to limit your investment to just markets you live in or normally travel to. 

Quote from @Victor Yang: If I gift a house, what amount will go towards the lifetime gift limit, the amount i purchased the house for, or the current FMV?

A third consideration is that FHA has rules for limiting rentals in developments. 

Coghill they are trying to take care of several things:1) Approval to access credit reportsA video tour of my home office (required by the credit repository to show security, so access to office & computers is limited to avoid data theft)Credit checks on me and my partner (required by the credit repository to make sure you are not criminals looking to steal others' data)Copies of the deeds for every property we own (required by the credit repository to confirm you aren't just self-serving)A copy of my partner’s home lease and utility bills (required by the credit repository to prove his legal address, so they can pursue him criminally if he steals data)Business phone bills (required by the credit repository to prove an actual business)2) Approval to use banking ACH system to accept tenant payments and pay ownersBusiness phone bills (required by banking industry to prove business legitimacy)A signed letter from the bank verifying our accounts (to prove legitimate business banking accounts.