1: The idea that only Jiraiya and Naruto can use Sage Mode, is balls. Hashirama used it, yet the toads made no reference to him ever knowing it.
2: Kishi is sadly pulling a lot of crap out of his anus these days and we all just kinda need to accept it. I'm not a big fan of how things are turning out and wish he'd not made the jutsu so ridiculous. I preferred the time when everyone still seemed a little human and meteors weren't falling from the sky and Susanoo didn't have legs...I don't know what's coming next and what Kishi will troll up for Sasuke, who got stabbed in the heart in a second by a man who Naruto fought head on with for ages, but I'm sure it'll put him back in the game via plot no random upgrade no f***ing jutsu.
3: If Minato had Sage Mode all along, you'd think he'd have used it against Obito when he used the nine-tails to attack..increased perception and all against someone he really coulda used it against...