Help with map creation issues

Hi! So I’m very new with modding and have lots of ideas but found no answers yet. So here are the questions:
• I want to add custom dino (Indominus Rex for example) to one or two of my biomes spawning wild. I saw it was realised on some very old map that was at modding contest. Cant remember it name, its not in workshop aymore. The goal is there were some small Snags and King Rex custom dinos on it and it was fun =)
• Is there any limitation of using extinction biomes and textures on map?
• Not found yet any info of how to add Scorched or Aberration engrams to be opened =)
• Do I need to copy texture files into my map folder if I using Scorched Sands like on Ragnarok for example or they will be gotten from game files on load?

Pls sorry for my eng =)
Thx for those who cold help