In total honesty(and in hopes that I don't sound like an argumentative idiot here
),the Inklings.Super Smash Bros. has always been about beloved characters of new and old battling against each other to represent Nintendo's long history,with each fighter having a staple representation of the generation and game franchise he/she/it stars on.The Inklings,are just way too new to already be considered as DLC to the game,and haven't made a staple place in Nintendo's long run yet as both Smash 4's and Splatoon's releases are far on between,and Splatoon was released one semester after that game.Personaly,I would keep them for the next Super Smash Bros.,as it would help more for the squid kids to grow into a franchise that's actually ready to earn their chance in the game.Generaly,they have to become a thing of their own for a period of time as a proper IP,and not just jump in the Smash bandwagon to promote the recent game even further.
Now as for the ones mentioned above,I would be a bit happy with King K Rool in;Rayman is actually one of my most wanted characters admittedly;Banjo would be nice;Shantae is fine too as one character that I gave some minor support to.
As for the veterans,seeing Wolf back would be alright for me(nothing special,but not too bad either),Ice Climbers would probably make me more interested,but not as far as my Wolf expectations,Young Link also would be pretty nice,and Pichu seems a bit odd with the support the Pokemon's getting,but the character really needs his self-damage issue from Melee removed,or lowered-down at least.
And Snake,personaly,I sort of just don't see him coming back soon(it would be alright if we returned in the game in my eyes).