I am going to reluctantly +1 this for this reason only
Draa utilized a RPS-6 rocket launcher, as well as a DC-15A blaster carbine and DC-15A blaster rifle. Draa was equipped with standard phase I clone trooper armor that was personalized in the green markings of the 41st Elite Corps. and an stylized asteroid on his helmet. He also made use of a backpack.[2]
It does state that he utilized HVO equipment, same as under Kix's equipment page it states he uses medical equipment, and he has medical equipment in game, and as long as there is a source stating a certain clone utilized certain equipment then I would say fair game.
Just make sure it is implemented correctly and the HVO slots remain fair throughout each battalion. If you do what you stated what would happen, I.E removing one HVO slot and replacing it with this lore character kit, I can see it as a fair implementation