Order of operations regarding metamagic

[The Sideromancer]

How is this resolved when one metamagic changes a descriptor? For example, can you have a Rime (Elemental {cold} (Fireball)) or an Elemental {cold} (Burning (Fireball))? going further off the second, is a Rime Elemental Burning spell possible?

[Claxon]

Rime Spell definitely doesn't work because Elemental Spell doesn't add/change the element descriptor to the spell. So despite dealing cold damage, it doesn't have the cold descriptor and Rime spell specifically says "Creatures damaged by your spells with the cold descriptor become entangled."