We have the 'Nothing preceded Darkness' assertion from the Andii and no objection from the Liosan when they briefly touch on origins in HoC
Also, one of the chained dragons in BH says something like ' even when Darkness ruled alone, there were elemental forces' and 'it is the nature of Darkness that it but rules itself'
Starvald demelain is consistently referred to as 'the First Warren'- easy to imagine the Elient as the first life, born out of Chaos itself, with some becoming the Elder Gods.
K'rul's intervention seems to occur in the aftermath of the Birth of Light but Cotillion says that K'rul didn't create the Elder Warrens so what use human warrens with no humans? Or maybe he did create the Elder Warrens, aside from KG and SD
Letherii origin myth - pseudo-scientific - the realm Forgers (Dolmen/Earth + Fire/Sun + the Errant's nudge to put Earth in the correct relationship with the Sun to allow life to flourish)
so I think I favour Eleint first with MD and Tiamatha the first to carve out realms for themselves within Chaos - Draconus, an Eleint, infiltrates KG, becomes Consort of dark, etc.
Meanwhile other Elder Gods are floating around with no realm of their own, born of elements/aspects present within KG and SD (Sea, Sky, Wind, etc.)
MD allows the intrusion of Light into KG while Rake goes off to kill Tiam, leading to the crisis resolved by K'rul in his creation of the other warrens, or perhaps his creating pathways between the realms.
Just thinking out loud here, sorry for the rambling
