First time grow it's the start of week 4 will...

No.

Based on previous question, this is an autoflower? I would not top it again. Most of the time, an auto won't have a long enough vege phase to benefit from this. It may work occasionally but consistency may not be there. Unless you've managed to delay flower, which again isn't something you can do with great consistency, it could reduce yield significantly. Were there any proflowers on the parts you pruned off? If so, it's already in flower several days by the time you can see them. hopefully the prunning delayed it so you have time for it to grow out. (Bwahah - @the_wanderer, nice )

Yes, that will slow it down even more. Nice stunting technique. More physical damage and stress and you can definitely reduce the harvest to an acceptable level. Check daily for signs of hermaphroditism in weeks 4 - 8 of flowering. Lookin good man.

if you want some symetry, wait until the 4 new are at least so long as their way to the stemcenter from their startpoint. and cut them all at the same time and lenght. then you have 8 mains. Which ist normaly enough if you use them in all directions on a horizontal plane. The streach will happen then verticaly from 8 strong Mains - resulting in a full tent.

not now. later you could