Hey Seuss! Welcome to C.com :thumbsup:

I'm hoping, and going to assume, you mean 12" in between the top of the container (the one you'll finish in) and the lights. How's come you've only got 12" vertical to work with? It's possible with heavy LST but will probably be difficult. May I suggest checking out some of the cabinet and rubbermaid grows? I'm just thinking with even a bit more space your options and chance of success will be greater.

My main concern here: Is it worth it? If you're not in a mmj state, growing tiny plants like the one you pictured in your first post would not be an option for me. That pic is not something to strive for. No offense to the grower, just my two cents.

One last thing, I'd separate those two plants into their own smaller containers. Watering will be much easier, root growth will be better, and it'll give them each their own space, as opposed to fighting each other for room.

Cheers!