USSEP Frost and Fire Dragon Correction

Inspired by this and this Reddit post, and the fact that I've (been moving towards a more vanilla Skyrim and) decided to remove any dragons overhauls I was using in my load order, I've made a correction for the prevalent Frost and Fire dragon spawning, which doesn't follow a logical pattern when using USSEP.

The problem

There is a discrepancy in the way dragons spawn in Skyrim, where one would expect each strength of dragons (Dragon, Blood Dragon, Elder Dragon, Ancient Dragon, etc.) to have a Frost dragon and a Fire counterpart. This would logically lead to the most variation, insofar as 'varied' is a thing when there's only a Frost and Fire class of dragon ;)

Bethesda unfortunately didn't take logical distribution into account and decided to create a levelled list spawn for two Frost Dragons at level 27, while every other spawn strength does have a Frost and Fire version. This was clearly an oversight, and resulted in seeing much more Frost type dragons in a playthrough. Bethesda tried to correct their own oversight with DLC 1 Dawnguard, adding two Fire dragons at level 59 to the levelled list (so you have a semblance of coherence regarding dragon spawning). The result is a Frost type and Fire type dragon for every Dragon strength, except for some weird reason at levels 27 and 59. It doesn't make sense, and the fact that Bethesda only tried to correct this with Dawnguard shows it clearly an oversight.

This oversight was also noted by the USSEP team, who 'fixed' this unbalance in Frost and Fire Dragon type by re-using the Legendary Dragon mesh for a weaker Fire variant that starts spawning at level 27. While this does solve the problem of seeing Frost and Fire dragon type more evenly, it also creates a new visual problem: you will see the Fire Dragon model mesh + texture too much in your playthrough, because the mesh + texture is used not only by Fire dragons spawning at level 27, but also by Fire AND Frost type dragons spawning at level 36. Weirdly enough, USSEP left the same 'bug' in tact when it comes to the two Fire dragons spawning at level 59, which should've received the same treatment as the Frost dragon at level 27. So USSEP only half fixed the problem (and that in a sloppy way).

The below table will visually demonstrate the problem for both Vanilla Skyrim and USSEP Skyrim; problem areas highlighted in yellow.

The solution

My solution is to incorporate a proper fix: I actually created a new texture for the missing Fire type dragon at level 27, and a new texture for the missing Frost type dragon at level 59. This will result in a balanced representation of Fire and Frost dragon types, and a balanced representation of unique models and textures with some increased visual variety :)

In short: there is much less Dragon el