Here, the lore is separate, at least because the attempts of parts 6 and 7 are ignored.
In general, the last thing I look at when adding new creatures is the official lore and whether such creatures are described in it. I don't care about it.
It is more important to logically connect the creatures: why is a species three times larger called the same as a smaller one? The idea of artificially accelerated growth at least explains this, and pharmacology is a much clearer explanation than the abstract "it's magic!", because in the real world, drugs can significantly increase size (although not to the same extent).
In general, pharmacology originated in antiquity, there is no reason not to use it in a fantasy world, and there is no reason not to give orcs leadership in this area.
Shamans and warriors actually look like the same race, unlike the giant leaders.
A goblin is not an orc. A centaur is not an orc. A wyvern is not an orc. A cyclops is not an orc.
Added after 38 minutes
By the way, dhampirs were also added to the game, and they are not officially present. And also cherubs. Gold dragons. Azure dragons. Marids.