https://www.youtube.com/watch?v=V9TNiDd-Ikw

https://www.youtube.com/watch?v=5eahp2ZM_uQ

Those videos should tell you everything you need to know about Barthandelus at least, if you don't mind serious spoilers for 13.

Potential Sin Eater material, yes or no?

As for Orphan

https://www.youtube.com/watch?v=YU-tGnrV4tQ