The area believed to be the Spider’s Heart was just a spot of brighter land and was blue, not red. The red spot looked more like a mouth of sorts and was the entryway into the Gate of Secrets atop the upsidedown spider like plateau which was believed to be Arachnia Plateau.
The Realm of Torment was originally Abaddon’s realm – like the Underworld was Dhuum’s then Grenth’s. It became Abaddon’s prison and afterwards, presumably, became Kormir’s realm.
As to the supposed Arachnia and the “gods of insectoid beings” being akin to the Elder Dragons in function – there’s no reason to believe such. Elder Dragons and gods are vastly different things, as “god” in definition of the GWverse in terms of the known physical gods hold indestructible magic – whether this is true for any god outside the Six Gods is unknown, but then again it is unknown if there even are gods outside of the Six Gods. Besides this, Arachnia and these other gods of insectoid beings are said to be long-dead, their corpses being within the Realm of Torment.
Besides, the Mists does not seem to hold magic. Or rather, it may but the Mists themselves are just protomatter and holds chunks of reality made from said protomatter; magic would be made from said protomatter too. There would be no need to regulate magic because it would be constantly made and, since magic is not infinite, used. Unlike on Tyria where we have no knowledge of it being renewable or being used fast enough.
Perhaps the underuse of magic in the Mists is what causes those chunks of reality to form, thus a regulation of magic would in fact make the Mists less of what they are. But it is pure theorycrafting and you might as well say that Balthazar was wearing a tutu while he decapitated his father – you have equal chances of being right in either case.
As to Fyonna – I see no relation, honestly. And I don’t think she simply transformed into a spider. I think the point was that a spider ate her or burst forth from within her (as it is said she stored her spider “babies” within her body). Sadly I never got a fight with her which wasn’t “pull her into the tunnel and stack on her!” so I could never see animations for it well.
To Fyonna trying to “wake” deities – again, I’d point to the fact that everything about these gods of insectoid beings is that they are dead. Not sleeping like the Elder Dragons nor imprisoned like Abaddon, but dead. And that pretty much says “no” to your theory like a giant brick wall.
And that’s even asuming Arachnia and the insectoid beings’ gods (nothing really says the gods are insectoid themselves, btw – or that the spider goddess Arachnia and the gods of insectoid beings are related) are canon.
