When a single Sapien is doing all the leadership tasks for a while, perhaps he/she would be named the “tribe leader”.
A popup “Your Sapiens have agreed that Sile should be the tribe leader. Leaders need to be protected because they are very important for the wellbeing of your Sapiens”, something along those lines.
When meeting some outsider Sapien, the leader should go straight there, and stand in front of said sapien, “talking”.
Just passing by and waving I don’t think that is very believable. This time talking would result in sucess or insucess, depending on the grade of the skill (probability).
If “Agressiveness” becomes a trait, agressive leaders would have a higher chance of scaring away outsiders if they don’t agree with staying in the tribe.