It's not perfect and I'm sure there would still be a lot of headaches to deal with.If I were to give a wink and a nod to edibles, salves, oils or whatever, it might stave off the smoking aspect of marijuana, but would still open me up to Civil Asset Forfeiture.  

I like this route and would add that there are options on the market that don't produce pervasive scents such as pens and edibles to help soften the blow and give them some flexibility. 

A few things I have heard proposed for them that might work, brewery, edible mushroom-growing, carpet square warehouse, mattress warehouse.

I would never put a rooftop garden in the warzone ghetto-- it's likely that either 1) what tenants growing is not edible, at least not food edible 2) some tenant will get drunk and/or violent and fall off the roof and sue the OP or 3) it will be a place where vagrants, drunks, thugs, and lowlifes congregate and either hurt themselves, someone else, or cause some sort of issue for the OP (noise, fights, parties, drugs, violence, juvenille delinquents, skateboarding off the roof, domestic violence, you name it).

It won't stop the edibles but at least we control the smokers.

We provide salt and pepper, no edibles.

Tell them they can do edibles, but serve them a 3-day fix or quit for the smoking aspect.

Hope you find it a nice non-edible home.

suggest edible marijuana?

I'm a co-owner of an Edible Arrangements franchise in Westchester County, NY.