I use semi-gloss on the walls and trim, and flat on the ceilings.

We have custom oak cabinets and the window/door trim is wood stained a medium brown, so we don't want to overpower the area with a wood grain floor.

Whatever you get, it should match the trim and finish levels of your rental.

As Keira mentioned, all houses built before 1978 have lead paint, unless all the walls, ceiling, doors, trim and everything that's painted have been replaced, or sanded down to bare wood and repainted. 

If you are fairly handy, LVP is pretty simple to install and you can use trim to cover up most of your mistakes. 

Knowing that aside from new builds, approaches may be limited to materials selection (targeting local and low/zero VOC materials), green cleaning products and potentially incorporating low maintenance landscaping (natives, xeriscaping, polycultures to mimic nature so they don't need regular trimming/maintenance), what else have you seen/used? 

These packages include a spreadsheet of Home Depot SKUs (for example) with all the flooring selections, cabinets, lighting, faucets, paint colors, trim, etc. already specified, and designed to go together design wise and be appropriate finishes for the market and asset class.

I would make sure locks were changed at turnover, common areas were well lit, bushes were well trimmed and general building security was maintained.  

Cost will depend on configuration, trim used etc. but I would anticipate you will spend $1200 to $1400. 

I will say this; slow down & trim up your team- times are a changing.