Hey guys! After lots of research and attempts, it seems Simple Spawners is the way to go for adding these spawns to your map. This was used for my server on ArkServers.io.

When placing a Custom Spawner (for modded dinos), use the following codes to Add Dinos to the spawner UI:

Blueprint'/Game/Mods/AncientWyverns/Dinos/Wyvern/Wyvern_BP_Fireball.Wyvern_BP_Fireball'
Blueprint'/Game/Mods/AncientWyverns/Dinos/Wyvern/Wyvern_BP_Ironbelly.Wyvern_BP_Ironbelly'
Blueprint'/Game/Mods/AncientWyverns/Dinos/Wyvern/Wyvern_BP_Vipertooth.Wyvern_BP_Vipertooth'
Blueprint'/Game/Mods/AncientWyverns/Dinos/Wyvern/Wyvern_BP_Ridgeback.Wyvern_BP_Ridgeback'
Blueprint'/Game/Mods/AncientDragons/Dinos/Dragon/Dragon_BP_Fireball.Dragon_BP_Fireball'
Blueprint'/Game/Mods/AncientDragons/Dinos/Dragon/Dragon_BP_Ironbelly.Dragon_BP_Ironbelly'
Blueprint'/Game/Mods/AncientDragons/Dinos/Dragon/Dragon_BP_Vipertooth.Dragon_BP_Vipertooth'
Blueprint'/Game/Mods/AncientDragons/Dinos/Dragon/Dragon_BP_Ridgeback.Dragon_BP_Ridgeback'

Hope this helps!