That's the thing, if they do, we have no clue that they will. GF has shown that they're not above playing favorites over the others, just look at Charizard as of recent years, so that may not matter to them. Sakurai could care, but from what we've seen, he hasn't picked either Charizard or Greninja because of their typing, instead they were picked because they were either popular/promoted or that Sakurai liked what the character can do. The trio and their typings was not highlighted in his reasoning, so there's little support that the GWF trio theory may matter.
That's not to say that Sceptile wouldn't be a cool candidate, I like the Pokémon and I plan on using him in the remakes, but I do think the GWF trio idea is being used way too much as a crutch to justify his inclusion. It's still basically a fanmade theory at this point, one that we do not know matters in the minds of either Sakurai or GF. So it's not nearly enough to push him to being a frontrunner as much as he has been, particularly if we're talking upwards to 90%.