No. Even with Ashes added there are still more shrines on Normal than there are in Elite and Ultimate: 33 in Normal while the other 2 difficulties have 20 each. Even with Forgotten Gods, only Ultimate difficulty has enough shrines to get them all in the one playthrough if you skip difficulties: 59 while Elite has 51 and Normal 47. You can find the list of them here:
Bear in mind that with Ashes the max devotion points you can have increases from 50 in the base game only to 55.
Not sure if this would allow you to switch it back or whether it just offers alternatives:
Yes, why wouldn’t they be?
Still mainly physique with only enough cunning or spirit to equip items. There are some builds that use more, but that’s still the general rule.