if this were to happen (which is very likely now that we have gotten confirmation of the rockruff thing) that would mean we have 6 new pokemon from the 3 starters.
And regarding Lycanroc, from what we know so far, the two forms function more similar to Meowstic. As we have not gotten confirmation that they have different stats, which many people are speculating they will despite us having zero clue except for pokedex entries(which we all know aren't always great *ahem*Pigeot's speed for example) as all we have right now is that the forms are version exclusive and have different move sets, which is pretty similar to Meowstic, who has 2 different forms with different abilities and movesets.
So that means if the starters do have the same "secret" then maybe the 2 versions of the starters will have the same type and/or the same stats; who knows? We certainly don't.