Bonus points on the fact they keep it in stock in store.  

take your bonus, pay down the home and sell it. not much creativity that can be had. if you try and short sell it the banks could still come back after you and it will crush your credit. chalk it up to a very expensive lesson learned - was it driven by FOMO of feeling like you needed to invest because everyone else was making money?

I know its expensive but you will be well protected :)Or you save a lot of money and be better protected by doing this consistently and well:-carry appropriate types and amounts of insurance-sign contracts with indemnification provisions- obtain all necessary licenses and permits to operate your business-ensure all vendors/contractors are licensed and insured and list you as additional insured-sign well drafted and fair leases and be a responsive landlord -be an active owner or hire an active PM  who avoids or at worse timely eliminates premises liability exposure The strategies you often read about are sold by alarmist asset protection companies who fail to disclose how impractical they are.

Assets identified in this study include:Bathroom Fixtures: Bathtubs, vanities, showers and toiletsStructural Components: Drywall, wood framing and interior partitionsBuilding systems: water heater, electrical distribution, HVAC, plumbingInterior Construction: Wood flooring, stairs, ceramic tileSmoke detectorsThis engineering-based cost segregation study included the following methodology:Physical Inspection through a site visitDocumentation review including architectural plans, accounting records and construction documentsA cost analysis which utilizes engineering principles in order to allocate costs to their applicable asset classificationsCalculation of the depreciation schedule using MACRSAs a reminder, bonus depreciation started to phase out in 2023.

Will they lose their ability to deduct bonus depreciation against their regular 9-5 income for all future years?

A syndication will only pay out quarterly and the bonus is towards the end when then sell/re-refi etc.  

Lastly as an illegal unit it is  huge liability if there was a trip and fall claim, fire etc your insurance may not cover.I recommend renters insurance for whoever lives there is mandatory to add another layer of protection. last option not considered is you living in the bonus unit to have a free place to live with minimal risk 

Just be mindful that georgia does not recognize bonus depreciation. 

Now using the de minimis/routine maintenance safe harbors instead of bonus depreciation for appliances, carpet and the like.

If you have some experience with buying and selling, for me, the best way to go is with a Flat fee agent that will put the house in the MLS and give it the exposure that any agent will give.