There are various issues with your plan.
3lb in a 4x4 would be packed tight and difficult to fit in and manage without airflow problems and mould.
I cant think of anyone who has pulled that out of a 4x4. Other than one guy running vert double stacked hps which changes the canopy size completely.
I wont say its impossible though.
Pulling a crop every month. That means your running a strain for 8 weeks and that has to include veg time, which you would need plenty of to pull 3 oz a plant. So that's not possible. Most strains will flower longer than 8 weeks anyway. Then you need probably 4 week veg. So take all that and your drying time and divide by the number of tents.
Maybe reduce your expectations and expand your time scale and avoid disappointment and then adapt and improve after your first few crops.
If you go with coco and cloth pots your going to have to raise the plants to have somewhere you can collect the run off.
16x 3gal cloth pots doesn't leave you any room for movement and for mopping up, makes it hard to water unless you go with automation, which would probably be the way forward.
Ebb and flow (not with coco) would decrease your veg time. You would be better with hydroton or grow stones.
