If this is their history, no special treatment.

This involves finding a reliable contractor, a property manager and a real estate agent who specializes in investment properties in the area.

I'm planning to keep my day job and probably look to partner with friends and maybe cabl dabble in some hard money. 

My team at Vested Alaska specializes in multifamily in the Anchorage, Eagle River markets.

Should I put in special tubs/showers or just hand bars, and provide a shower seat? 

I payed special attention to the first few guests because those reviews are so valuable.

Consider specialized insurers like Nationwide, Farmers, or Liberty Mutual, which may offer policies tailored to multifamily rental properties.

I focus primarily on the upper valley but I can refer you to people who specializes in the Brownsville/SPI area.

I'm not a CPA (although I do know a great one that specializes in RE specifically) but you can run a cost segregation study to accelerate depreciation into the first year to help on taxes (although this is phasing out, but can still be powerful), and may help with your plan to do Roth conversions. 

These specialized companies, easily found online or here, will create your company's SD 401(k) plan.