Yes they can. It's actually fairly easy. It may not be entirely accurate, but they can roleplay it just the same. Just like I can roleplay a Tabaxi as a cat person, even though I'm not one.
I see my players do it when they have a low intelligence. Now, when the players are talking out of character during the week about what they want to do in the next game, the players will sometimes give a different opinion and/or use their intelligence, but in the game the character isn't roleplayed as a great strategist.
Okay. Instances of some people getting it wrong is not proof that it can't be done. I've seen low intelligence, wisdom and charsima roleplayed well quite often.
Absolutely false. That is not the only true measure. Those things are simply the mechanical measure.
If a PC has a gift with something, the player and I will have worked that out.
And that's false. None of those in my group are even decent actors. Hell, we're not actors at all, and yet we all roleplay these things just fine.