Another way you could qualify for a conventional mortgage(without going the creative route) would be find a co-signer.

Hello allI recently had a conversation with a co-worker who had just formed a 3 man LLC and financed their first purchase. 

Used conventional renovation loan with 20% down and borrowed my Dad's credit as a co-signor.

Also, being that you are a licensed massage therapist (according to your profile), it might make sense to do something like this, as it can provide other forms of asset protection to protect you further from any potential claims that could arise in the future.Also, sometimes the easiest and simplest solution would be to find a co-signer.  

Is it possible to remove him and just make him like a "co signer and still make him financially responsible if she falls behind.

Is this a co-op or a condo?

If you want to explore this option, I would recommend:1. instead of your long-term tenant having their own Airbnb hosting account, you can add them as a "co-host" to yours. 

You may want to consider additional collateral, a down payment or even a co-signer.

Do you need to deal with a Home Owners Association like in a CO-OP?

My bigger fear is that it is somewhat likely that the father isn’t really moving in and is more of a co-signer than a tenant.