So you're renting the place and providing the setup so they can grow weed on property that you're attached to? I don't care how good a friend of a friend they are, that's trouble waiting to happen. There is literally nothing keeping two guys who don't really know you from leaving you hanging. If that place gets raided, it's linked to you. If they decide to rip off the grow and head out of town, there's nothing tying them there. You're taking most of the risk. Not to mention, trusting alot of people you don't know well in an environment that makes it very easy and profitable to rip you off. Who's footing the bill for all the equipment and genetics? How many times have they grown the strain on a large scale? Do you have all the details decided? Also, do you know for sure these people even know how to grow on that scale? Or are you just assuming that these growers haven't gone "Closet, commercial, meh, it's all the same."?
I'm not saying don't do it, obviously I don't know all the circumstances as well as you. I'm just saying that just because they're his friends, doesn't mean they are your friends. Also, if you do go through with it, make sure these growers really know their shit. There's alot of weed barons jr.'s running about these days.