To a complete stranger, it sounds like this:
- Savage experienced several traumatic situations that have made him fearful and prone to growling at Jade and Kasie
- Savage is considered "aggressive" by your mother and is therefore disliked, and the dislike is obvious to all
- Savage is forced to live outside and can not, under any circumstance, come in the house to sleep
- Savage is unfairly reprimanded when Chloe has instigated the growls (BTW, Savage growling at Chloe is completely normal and GOOD - Chloe needs to learn her boundaries and Savage is showing normal, healthy dog behavior)

I honestly don't know where to start with this. I know that you love Savage very much, but if you want Savage to be sincerely happy, you need to talk to your mom and ask her to start treating Savage with respect. This is your first step because curbing aggression or whatever it is that Savage is displaying takes a long time to work with and it requires effort from ALL members of the family.

Secondly, it just doesn't seem like Savage and the humans are connecting. I don't think Savage understands human body language and I don't think your family members understand dog body language/mindset. If Savage lived as an outside dog, he has rules about space, resources, and leadership, but humans have not played a role in any of those things. If you want to integrate Savage into your human family, you all need to learn "dog" and you need to help Savage learn "human". The best way to do that is to contact a behaviorist who can work with you personally

(In the meantime, buy these books: The Other End of the Leash by Patricia McConnell, Don't Shoot the Dog by Karen Pryor, and Culture Clash by Jean Donaldson. They will help you to understand what Savage is really doing by growling and why he's doing it.)