The warranty people talk about really isn't of value in most cases. 

You could always get the extended warranty and still save money over the 3k model.

Schlage has a 3 yr warranty on electronic locks and the UPS you a replacement after a few photos and a quick phone call. 

However, the simplest way for an intra-family transfer would be to quit claim deed the property to your sole name/entity, which comes with no warranties or guarantees. 

Even using dedicated independent contractors as your maintenance crew requires book keeping (bills receivable, payment, bookkeeping to track expenses for tax purposes and warranty claims, etc.).Having a reserve for cap ex, but not allocating any estimate for the cap ex cost means that your cash flow estimate does not include cap ex. 

One wanted a used replacement to save money, while the other insisted on a new one with a warranty.

If no mortgage and/or if the mortgage and the lease doesn't restrict assignment, then you can set up an LLC, warranty deed the property to it, and assign the lease.

I would make sure a bundle of rights for ownership are available individually, per unit of course, then worry about warranty and purchase options.

The warranty is an absolute joke, please read the fine print. 

- In Michigan, you only get a tax deed when buying at county tax foreclsure auction, not a warranty deed. - Lenders will NOT recognize this deed.- You will want to find a title company willing to research (for a fee) if county met all state legal requirements on posting proper notices for their tax foreclosure.