[@WrongEndoftheRainbow]
An interesting idea, the Phoenix is indeed a legendary being but it might not work out in this scenario that we are in unless the GM approves of it, but I'm just stating my opinion. As the word Phoenix itself can be used as a name for a species of elemental spirits, unless you make a nice twist to it which I'm fine with. But even at that point, Phoenix would be more or less an elemental spirit born from the world itself more or less. 

The only solution I would see with your servant is to make it a counter-guardian by the meddling of Gaia to stop Alaya from doing her shenanigans. But I'd wait for Dawnscroll to come back before seeing what he has to say about the situation, I like the idea though!