I've been doing a fair bit of reading up on Angels in the forums and there seems to be some confusion and a bit of a gray area regarding the binding of Angels like immortals so I just want try and get a good understanding if possible...

Is this because those angels are still living entities and/or because their spirit is simply too powerful?

Which Angels can be spirits and bound in the same way as is typically discussed for spirits and which Angels generally can't be bound in that manner, but rather can only be bound in the same way that immortals would be?

Would it be safe to say that any Angel of an equal or greater rank than an Archangel could only realistically be bound like an immortal? And all Angels of a rank lower than Archangel are able to "die" and become spirits that can be bound?

How does all of this apply to Fallen Angels?

Mm there is spirit binding, e.g.:
https://shop.creepyhollows.com/CUSTOM-C ... ERFUL.html
and there is living entity binding, e.g.:
https://shop.creepyhollows.com/bronwyn- ... nding.html
Immortal binding is another type of binding.