Hello,
Hope everyone is happy & safe wherever you are.
Why did I want Amelia as a mother figure to Harry?
Amelia was a good aunt to Susan as per cannon & she was a very 'just' person. So how do you think she'll end up raising Harry and her own child?
She'll tell them the whole thing they need to face before itself so that they can be prepared. And she'll never force any kind of responsibility on them like "Harry should fight because he's the chosen one" or anything like that. She'll leave the choice with the children and support them in whatever they do while ensuring their safety without fail.
Also, she'd never ever make them miss out on their childhood over 'prophecy' & 'saving the world'.
If I have to say it simply she'd be like: " I don't give a d*mn if the whole world is in chaos. I just need my children to be safe & happy. If they choose to fight then it's okay. But if they don't and you guys wanna force them, I'll avadakedavra you into hell" Well, That's how she'll feel even though she might not curse out like this in front of others...
Some might feel that 'she's a very just person and a righteous person and all... So why wouldn't she want Harry to fight?'. She'd never do that. When it concerns their children no parent would want something like that (mosly. there might be exceptions ). She'll fight on her own against Voldemort & would never want her children to fight, even if she knew they need to. But if the children themselves choose to fight, then she'll make sure that they're fully prepared for it.
Don't you think she'll be somewhat similar to how Sirius was in the actual cannon? However even Sirius tried to hide a few things. But Amelia would not.
That's it.
And I think Harry would have had a happier childhood if Amelia and Sirius was there.
The most important thing is that I ship Amelia and Sirius so hard that I'll be happily be their matchmaker if they were in front of me.
Regards,
~Illy