I've wondered about a hypothetical like this.
I suppose you could leave it all as is and just tell him you're growing tomatoes or other fruits/vegetables or whatever. I doubt the insurance guy would care WHAT is growing in there, though his beef might be with the tent and setup itself. But you could still be like "Look, I don't want to disrupt the process at this point, because the plants are delicate" but if you want me to shut it down and remove it all and stop doing this, I understand and will start doing it right after you guys leave emphasizing that the reason you'll wait for them to leave is so you can optimally and without disruptions take your setup somewhere else to continue growing instead of juggling the inspection as well as that whole project.
Matter of fact, what I just thought of is that since you have a few days to figure this out you can just be honest with the landlord and be like "Hey, I'll be straightforward with you I have a grow tent in the apartment growing plants/vegetables and just to get complications out of the way if that tent itself is going to be an issue then I can just break it down and move take it somewhere else because I do want to continue renting here". I would think at this point the landlord may kind of guess what you're doing and if it bothers him then he'd tell you to get rid of it and not being a jerk and actually calling you out on what is he suspects you of growing. If he does want you out of there then I suppose he'd just tell you to get your stuff and go because he's already come to a conclusion. Risky to some, but I do stuff like that. If dude wants me out, fine with me I'll go somewhere else and he can have fun finding another tenant.
But if he respects you and says the tent is fine but it does have to be vegetables then maybe just buy a couple vegetable plants and chuck them in there for the couple hours or whatever they're going to be floating around while you stash your plants somewhere else for that period to pretend it's actually vegetables and stuff, lol.
Anyways, that's what came out of my mind when I read your situation.