is the purple on the leaf branches good or bad?

It could be signs of a Phosphorous deficiency, but not with your plants at that age, you'll notice it much more likely in mid to late flower if it's phosphorous. Sometimes it is just the strain in my opinion as I've had purple petioles before and the plants have been perfectly healthy. I wouldn't worry about it unless you see other problems alongside it like necrotic spotting on the leaves etc.

There's a lot of speculation on this. Some say plants grown under LEDs always do this. Others say it's part of a deficiency. Still others are just a strain trait. I wouldn't put too much stock into it to be honest. My plants have gotten purple petioles and turned out fine. Mind you I mostly notice it in flower.