I don't think there are "phoenis lords" for the Shining Spears and Warp Spiders.
As we all should know, there are lots and lots of Aspects - the most common ones being Striking Scorpions, Howling Banshees, Fire Dragons, Dire Avengers, Swooping Hawks, Dark Reapers, Warp Spiders and the Shining Spears. Now, we know that they're the most common - but that doesn't mean they necessarily have Phoenix Lords.
For all we know, Shining Spears were started by an elite cadre of Guardian Jetbikers, or even Dire Avengers who used jetbikes - becoming Shining Spears. Thus, they don't have an individual creator, but rather a group - they may have simply risen to popularity because the young Eldar think "Hey, that's pretty cool" or because they're dangerous aspects and thus they think they can prove themselves more.
I know it's kind of a bad explanation, but it's the best I can think of - perhaps they simply don't have Phoenix Lords
