I like your guides. Thank you for not presenting these as "This is the BEST variation to use" etc and instead just present strong options for the viewer to pick from.
Also, I would like to give my feedback about Spawn;
I agree with what you said about Glide. While it does serve a purpose of giving him really efficient damage in The One (40% 1 bar stuff) it doesn't really do anything else despite having the ability to do it 3 times before landing (at no real benefit).
Raising Hell is really strong for what it does which is why it conflicts with Phantasm. If I could have both moves I absolutely would do so. It also pairs quite well with Charging Hellspawn, but personally I also prefer Phantasm. Being able to d1~Raising Hell is pretty handy and at best they trade with Spawn if they also did d1.
Very few characters get to enjoy that level of safety.
Blaze of Glory can also catch d1s. Additionally, when the parry is triggered Spawn can still cancel the stance and convert into a full (but scaled) combo.
If said combo is a launch, such as b12, a successful armor break effectively eliminates this combo scaling.
This makes it continuously strong even after the KB is spent.
Instead of trading like Raising Hell for doing d1~BoG against someone mashing d1 back you'll just beat them clean (whiffs on Sub though).
You mention it doesn't compete with anything, but it actually conflicts with Plasm Pool which is honestly a pretty cool ability that is heavily unexplored.
Leetha Stance can also launch in the corner for the same reward as using it as an anti air.
Plasm Pool is neat since it greatly speeds up Spawn's meter cooldowns but it also slows the opponent's by the same amount if they're touching the pool. This lets him do some annoying stuff like plant it on you in the corner and continue pressure using Raising Hell or Hell Chain. Placed perfectly it can cover both players while Spawn continuously shoves himself back safely to where he can continue being oppressive. This also makes doing things like invisibility a lot more meter efficient too.
It also pairs decently with Charging Hellspawn (like everything, lol) since using this move is naturally rather expensive for his resources when he wants to lay on the hurt, only now he regains those back faster.
Soul Forfeit can be activated twice in one game, I just wouldn't.
I am really glad you brought it up as I think it's a pretty slept on playstyle for the character (I liked the moral compass joke too btw, lol).
Round 2/3 cleanup or "win more" style toolbox for dumping our remaining KBs on a sucka.
A hidden aspect of Soul Forfeit is that after activating it, but before using any KBs, he can use the triple grenade startup on his fatal blow as if he had used Invoke the Legion (which literally has no point now).
More than just removing the wait time from the Leetha stance KB, you could have ended a combo with it after the b12 launcher in your footage at that moment, which is the main reason for the scaling on them for the privilege.
Pretty much the only move I think is actually bad is Invoke the Legion. Even Guns Blazing has match ups it's useful in.