15 seems about right if you aren't going to cover LN15. The anime suffers from not introducing the Orphanage and their importance to Syr. There is a lot of time devoted to them and it humanized Syr with the later reveal.

It appears there will be 5 EPS for each LN. You could easily do LN18 in 3EPs. Or better yet just watch the intro.

Yeh, it’s too short but it’s not like they could have done a rightful adaptation after Season 2 cut content so rewriting is the only decent option available.

I am looking forward when Hestia breaks the spell is a momentous scene.