@Budda Yes they can, I just tested this when I got home. Sorry for the delay.

If they are "optimized", why is there even the option!?

Have you tried L and R, and then hitting "a"? I seem to recall in previous iterations of the game that was how you performed a give and go.

All the other answers give reasonable descriptions of why someone would make an early Evo Chamber. If we are talking about an inexperienced player, simply guessing at reasons for why they would be wasting 125 minerals and a mining drone could return hundreds of answers. Why are you more likely to believe this rather than they might be either a) preparing to strongly defend and turtle in their base by having a detector and anti-air defenses or b) discourage a scouting player from a cheese build because of the existence of the detector?

For strategies on how to cut them, use all your fingers! Don't start cutting until it reaches the top of the trajectory, and pay special attention to the smaller end of the carrot as it has a lot of places it needs to be cut to get credit.

Yes, exactly. Once you move them in the Windows explorer (using cut and paste, or drag and drop), they will show up in the game so you can replay them back.