Currently, a single-family home costs you $430k median, and rates sit around 6.75% still.

To me, I sold all SFR to buy industrial single tenant NNN.

I like the suggestions that said to buy a place for yourself whether that is a single family, a duplex or fourplex.

For single-family rental homes, is it normal to have a waiting period of a few years before cash-flowing? 

No, it only applies to properties held for production of income (rentals) or for appreciation (land) or both.

Are there any recommendations for a solid single resource to give a collective overview of home system life spans to support life cycle planning?

Your PM fees will also be less per unit for a multi unit vs single family.Tenants in multi unit buildings share walls so there is always the potential for noise complaints and neighbors that simply can't get along with each other.If you run into financial difficulties, it is much easier to sell off one or two SFRs than it is to sell one big multi unit.Traditional lending is much easier right now for SFRs vs multi units.  

Your example of the ice machine or other hallway areas in hotels doesn't hold water, because unless the hotel vets every single person that enters that establishment they have no way of knowing whether the person is a guest or a bum or a robber.

It also really depends on the actual product.

The properties are high equity single family homes in A to B area(s).