To say Zero Suit Samus is super far removed from her appearances in Zero Mission and Other M is kind of wrong though.
Captain Falcon was a 100% original creation - until Brawl introducing the Blue Falcon as Final Smash, there was 0 references to his series beyond him being fast, not even any references to the comic that came with the SNES game, like the gun he had in that one.
Zero Suit Samus still heavily references what she does in Zero Mission (both with the stun gun and the crawl, for instance), and a lot of her moves aren't that far removed from what a suitless Samus could do either. Remember that she's a super athlete with Chozo genes in her body. The only things that are completely original to her Smash incarnations are the laser whip and the rocket boots, and the rocket boots aren't even out of character for her either, even though people don't like the design.
The whip is the one thing I'm probably the iffiest on from a Metroid series representation standpoint, but I also understand that Zero Suit Samus didn't have a lot to work with, and a character with a whip didn't exist prior to Brawl, so I don't fault Sakurai for taking a few liberties with it. It's probably the least believable out of all of Zero Suit Samus' abilities and gadgets, but it's still feasible for a sci-fi series.
Also, let's not forget that the rocket heels were introduced specifically in Smash 4 when pure tether recoveries got kicked into the bin. In Brawl she had another whip move.
