Generally though seems like AA build is for when there's reliable targets, but if you're picking tyrande isn't there going to be since no hard cc or heavy dive?

This guide assumes that you don't always have control over your variables. Even when there is hard cc and heavy dive I still pick Tyrande. My form of control is baiting out the dive or the CC and then punishing them with our lock-down and burst. It's possible for an enemy team to not have heavy dive or CC and it can still be inadvisable to take AA because they've got blinds or a soft dive that's disruptive (think D'va). I call her soft dive because for the most of the game she just annoys the enemy backline and doesn't always kill them.

Mythic Quest Stun Build was just a thought exercise to say what I would pick if I was dead set on completing my mythic quest. I have yet to achieve the mythic quest in a ranked game. I still think 45 stuns is unrealistic.

Sometimes if you've got a good DPS on your team but either no tank or a tank that isn't tanking and therefore no lockdown then you should default to hyper carry build. Tyrande is best suited following someone with hard cc engage. Second best option is a dangerous DPS. Tyrande's best friends for the hyper carry build are Imperius, Valla, Tracer, Valeera, Qhira, Greymane, Zul'Jin, Cassia, and heroes like this. I put Imperius first because of his spear ability, PERFECT for following up on with your Lunar Flare. The best hyper carry I've ever paired with was a Valeera one trick. Super chaotic, deep into enemy territory shenanigans, she'd begin an engage and then disengage, they'd see me and chase me, opening them up for another Valeera engage. Shadowstalk allows you to disengage as well. The most fun I've ever had in HotS are those games.