IMO this is much too little additional return to put your personal residence at risk.  

NEVER borrow from a 401K, you are taking pre-taxed dollars and paying it back with after tax dollars, you do not get to return the loan with pre taxed dollars, in addition, some 401K plans do charge interest and maybe even fees, and lastly if you get laid off for some reason, it is a distribution with all the "fun consequences: tax at the last dollar rate, and if you are under 59.5 there is also the additional 10% penalty.Personally I like the HELOC, however you can also sell stocks and do tax harvesting there to offset gains if that is an option

All this in addition to 6 other lease violations... 

Feedback has not suggested property needs additional repairs/work, only that they are looking in a different area.

Be prepared to come in with additional cash to close due the the appraisal.   

These platforms are affordable and offer comprehensive reports (credit, background, eviction history) without you having to handle sensitive information directly.Verify Employment and Landlord History: Your plan to request pay stubs and a landlord reference is solid.

In addition to refinancing, DSCR loans, and cash-out options, we now provide our services for all property types, not just those from NetWorth.

Most likely a "discount listing" Owner pays realtor a small amount upfront to add it to the MLS.

Additionally you can do a cost segregation study and get a lot of depreciation benefits to offset the rental income (and potentially other income).  

In addition to that, building your network is key.