can everyone press 2 adjacent ....
I would tend to doubt it, & have no special knowledge in the area.
I've known 2 folks who have short tendons and have small inconveniences (for example can't type normally on regular keyboards) because of it. When I talked about it with them It's a "condition" that only a requires their structure be a tiny little bit out of the norm - just as one example, the finger beside the pinky is very mobile for a lot of people and very immobile for a lot, and the anatomical difference that produces the difference is tiny.
And similarly I bet some folks could hold down a whole row (like a guitar barre)