As for hyperspace and gravity wells...
That was more something that WEG made up to account for the " why didn't they just jump to hyperspace right away?" in ANH when the Falcon was fleeing Tatooine, when really it was probably a case of Han not having the coordinates to jump to Alderaan plotted and loaded into the ship's navicomputer. Remember that they did have to take off in an awful hurry, and I doubt there's much in the way of a common route to go from Tatooine (galactic backwater) to Alderaan (notable core world). Luke dropped out of hyperspace well outside of Dagobah's atmosphere/gravity well because it was a completely foreign planet that he knew zilch about. Other authors pretty much took WEG's answer and ran with it.
But in the new films, it does sound like jumping into or out of hyperspace from within a planet's atmosphere is a very risky proposition, and I think there was an episode in season of The Clone Wars were a Republic warship had to do an atmospheric jump to hyperspace that wound up causing all sorts of issues for the ship. So it sounds like the heroes of the movies have either been very lucky (Rogue One crew) or really good (Han Solo in TFA) when trying that particular stunt.
Gravity wells preventing hyperspace travel is canon. Hera talks about it in iirc season 1 when they change course in hyperspace. It comes up again later when the ghost meets the Purrgil in Season 2, Episode 13 "The Call" when Hera explains that the mass shadow of those space wales destroyers ships when they cross the path of hyperspace routes.
Basically Rebels is using all that EU and RPG infos while the freaking movies just showing us incorrect visuals. IIRC JJ himself stated that the starkiller weapon fire was not really visible in the whole galaxy, it was just a metaphor. Once you are down that the visuals don't count anymore, you can ignore those movies safely on the details when considering what is canon and what is not.