That's just speculation with no evidence. And those druids worshiped the artificial gods, just like the rest of Eora, so they were doing their rituals within the system.
That much is implied in POE 2, yes.
No, it is stated in POE2 that with the Wheel broken there will be no rebirths, souls will go to the Beyond and won't return. And sooner or later Eora will be void of life, because souls won't return to inhabit the bodies. So it's very ****ed up now thanks to Eothas.
And yes, somebody will have to fix the Wheel pretty quickly or everything will die out. Eothas called it as his test to kith. What a douche .
No, it is stated in one of the dialogues with the gods that they still could but decided not to inhabit physical bodies anymore after Ondra killed Abydon. Too afraid to start killing each other again? Kinda weak point considering Eothas threatened their whole existence. And now they're ****ed too because breaking the Wheel also broke the In-Between from which they siphoned souls to sustain themselves.
So we will be looking at a worldwide Hollowborn crisis?