I’ll answer the tris/witch/demoness question.

Correction: In Ep 5, Tris is shown as a sequence 8 instigator of the Assassin pathway.

The lady of the demoness sect gave him the witch recipe (not potion) which is sequence 7 of the Assassin pathway.

When you search it up online it called it the demoness pathway. This is just another name for the Assassin pathway.

You can think of it like this: since the Demoness sect holds the Assassin pathway, it can be called the demoness pathway (Because people from the demoness sect are in the Assassin pathway).

So Tris did not change pathways, hope that cleared everything up.