The manticore either needs to be incredibly cheap, given an armour save (or some way to icnrease resilliance and durability), treat like minor mounts and blend their stats with the lord or a mix of the above.
They are literaly a liability for characters whilst simultaniously making them a bigger target and alot richer.
"He who studies evil, is in return, studied by evil"
Well, if we want to give the gifts and blessings the real chaotic feel, why don't we go and give all the marks a small table to roll on. As I said, I can't see these unfortunate ones who receive a blessing that shreds their mind or destroys their body ever reaching this exact battle you're going to play. ONLY the warriors who can fight, can survive, will fight, because if they can't, they're already dead before the fight starts. Ok, some slight debuffs, like Khornates having -1 WS due to being careless is understandable. Nurgle having -1T? Breaks tradition, and weakens Nurgle to be useless when comparing to the others. Unless they all had similar debuffs, which they don't in your list. Marks have to be equal.
If we want to make this game "realistic" in a chaosy way, we need an unlimited table, and every warrior in the army rolls separately. Every last marked one. And, just to make it a bit more complicated, every God has his own table or six. We don't want this game to be too complicated to play. I say each Mark should grant a minor buff, or a bit larger buff and a minor debuff, but keep it simple.
Or let's take an even easier solution, have specific units for different Gods, like Daemons and Chaos Marines do. This way, each God's unit is different, even if they use the same base idea. It's like having Marks, but made clearer and easier. As much fun as random effects are, you can have too many in one list. When I play, I don't want to have a notebook next to me all the time. I hate having to make notes during a battle just to keep track of who has what. Currently I don't need to, as mostly only Chosen get more than one roll on EotG, which works well enough. Heck, even keeping track of Dark Eldar pain tokens annoys me a bit.
"Horrors are Pink, Horrors are Blue.
Where once there was one, Now there are two!"- Liber Malefic -