Yeah man you are right! yes about those Nether dragons, and such. Especially man about that about Wc1 and stuff. I don't know many about races, I am expert only about Fel orcs. For rest races.. nah I am not expert you know probably better than me.
But I didn't say that Fel Guards are fel orcs. I told only that fel orcs are supported by demons, and they are similiar to them.
You see in link you psoted this writes
,,The felguard are the Burning Legion's rank and file soldiers, and are conscripted from the mo'arg demon race.
The felguard operate under the direction of doom guards, pit lords, and other Legion commanders and generals"
Well Fel Orcs are some demonic races too, they are under demon's serve too, They are red skinned and have chaos damage like Fel guards too. And they live in Outland too.
But look at this now
This is fel orc warlord, but it is used also in some demons maps. So would you notice difference if he didn't name it ,,Fel Orc" only just Warlord?
Also look at this
And especially this one
You see first one is named just Fel Rider! it isn't named Fel Guard rider! because author as meny people I saw in their maps since I was moderator, they are using it as fel orc!
Especially this second one! You see that second one is also Fel Guard riding FelHound beast!
But General Frank made it as Fel Orc! Because in apperiance there is no difference between Fel Guards and Fel Orcs. You see I saw in some map, one guy used Green Orc skin for fel guard, so it became typical orc. Same as Red Guard version. Its similar to chaos ones!
Also please look at this
This is another Fel Guard riding car, but it is named ChaosOrc!
Because it is same so you can use those models both in both demons and chaos orc race. Of course not if you have both races in one map!
Plus those buildings General Frank made, he is using them in both Demons and Chaos Orcs because they are similiar.
You saw his Altar. If it is used by demons it's named Altar of Terror, if used to Fel Orcs it is called Altar of Chaos...