Dimensions and number of plants

That’s going to be tight. You would have to keep them to a max of 1 week veg

Just go with Scrog, HST and/or a shorter Veggietime if your unsure... You could look up how much max space you got with the Lights for your Plants and Mark that spot, after that divide the length of that with 3 and you got the hight in wich they are ready to change into flower if you want to get super sure about space. 👍

not a chance I have 4 in a 1.2 x 1.2 x 2 and thinking its too many lol you may get away if you let them grow straight up

great question, difficult but not impossible, first of all 4 different pots with 4 plants will give you more yield even if small than 1-2 alone even if they are big later. Up to here it's positive. Your box is really small. My real question is do you really need the box? Because I'm currently doing 6 grows but only 1 is in a box. If you can't do without it, use LST, SCROG, pruning nets, etc.