There's a great treatise on the seven forms written by one of the resident masters, and unfortunately the link to it doesn't work. I've messaged him and hopefully he will get back to me and get me a copy.
Is Vaapad more about using Djem So with Ataru, Soresu, Makashi, and Shii Cho while maintaing minimal defense and giving a lot more attack? And if so, would Juyo use Shien mainly for the Form V aspect? Plus I heard it's a lot more hybrid and a part of all forms like Form VI Niman.
The answer to all the questions asked here is "No." There's so much wrong/misunderstood here that I'm not even quite sure where to begin...
But I'll start here:
https://thesnarksideoftheforce.wordpress.com/2016/11/15/form-vii-juyo/ and here:
https://starwars.fandom.com/wiki/Form_VII and here:
https://starwars.fandom.com/wiki/Form_VII/Legends I think the basic misunderstanding here is how the forms work. While they are built on each form before them, they are unique and independent of each other. One form doesn't use the techniques of other forms, they have their own set of unique ones. I guess another way to put it is that, in learning a form, you're learning how to learn the next form. Fundamentals, basics in footwork, movement, mentality, etc. from one form are built on in learning the next one.
You can ask the resident Masters (for example Master Nero Attoru) from TPLA for an "official" statement, but here's my thought of Juyo/Vapaad:
Vapaad/Juyo as Form VII are relatively new compared to the "early" ages of the Jedi Order. Both are more likely outside the actual progression, as Juyo and Vapaad heavily rely on emotions, making them very dangerous. To enemies and the user itself, as it brings you to the edge of the Dark Side. That's why it's not officially taught by the Jedi Order and that's why it's outside the other six Forms and not really comparable to them.
Form VII is all about attack, but in a different way than Ataru and Djem So/Shien. IIRC, Form VII uses staccato-like attacks, always altering the directions so that the enemy can't work out a strategy how to break through the barrage, it's almost unpredictable. And every strike is fueled by emotions, especially the emotion that is described as "accepting and actually loving the fight". Since this relies on emotions and actively attacking the enemy, you can see why the Jedi are so eager not to teach it - it's actually against the Codex.
Correct me if I'm wrong
That's a pretty decent summation. The only thing I would add is that, while I normally refer to Master Nero as he's probably the most active TPLA member on the site, it is (or at least was) Master Artorius who was working on developing Form VII for TPLA. But contacting Master Nero would probably be better as he's here much more often.
The only Jedi authorized to teach Vaapad was Mace Windu, and he only taught it to one student, who, depending on which lore you're reading, didn't cope too well with it. There were other Jedi with knowledge of Form VII, such as Yoda and Cin Drallig. But, as Yoda said, "Six there were for generations of Jedi. The seventh, is not well-known. Powerful form it is. Deadliest of all. But dangerous it is, for its master as well as its opponent. Few have studied. One student alone, to mastery has risen."
