there might not be a new sage but if i can see why people would assume that naruto would be the new sage. but wouldnt the sage be reincarnated, if he is being reincarnate, as a senju or uchiha
question 1: kakashi didnt go to obito's dimension
question 2: i doubt it
Question 3: no he cannot choose where things get warped to
question 4: no he cannot
question 5: it stays in that dimension
question 6: it is unknown
question 7: i doubt they do
he could seeing as they're related but its incest and they don't know they're related plus I don't think he would go for her seeing as she counts as a criminal.