>>527100047
>nor does she have any strong dynamics with anyone.
She has a strong dynamic with Sonic, Amy, Knuckles.... And Tails is a major character in the Rush series as well, I guess...

So, I see no problem here.

>>527100047
>She doesn’t belong to their world at all
Just a more extreme Knuckles situation. All this really means is that there's a hierarchy:

1. Sonic
2. Tails
3. Amy
4. Knuckles
5. Blaze

The higher the stakes, the more likely the others appear. If its a simple casual whatever adventure, then Tails and Amy at the absolute most could appear just to be there. If things get a lore more serious and lore heavy, Knuckles has a good reason to show up. And when things get really crazy, Blaze arrives. And when its time for a RACE, Enter, the Sixth Ranger: Jet.

But in the end, the main focal point is always just "Sonic the Hedgehog".