[First grow] Should I remove one plant to maximize yield ?

In general you will get between 2-3x as large during transition from vege-to-bloom before the vege growth stops (stem elongation and new leaves) bend and train into an L-shaped plant... as best you can... or prune them to fit --- can keep both plants if you want to. if you think 1 "can" fill it out... that could work too. Yield will be similar if the space if fully filled one way or another... soem strains produce denser buds than others and have a higher potential per sq foot, obviously. Keeping both hedges bests a bit.. if you know one produces larger, denser buds and yield is primary concern, then picking one might be best for that context? Do what is best for you... can one of those fill out a 2x2? maybe. you'll probably squeeze more out with both plants in there and bending, twisting and lastly pruning as needed. 2x2 is the space... fill it as best you can. don't worry about some minor unorthodox options... in future you'll plan better and not over grow for your space. 2 plants i a 2x2 have to be rectangular in shape to fill it optimally, for example. So, you shape them that way from the start. figure when it is 70% L x 70%W (=.49) then you have room for a 2x stretch.