Bon Chan needs to be played by a non binary actor, that would be more respectful of the character and non binary people in general. I'm not a specialist of Non Binary actor but I've made a bit of research and a few names seems interesting:
J. Harrison Ghee
Perfect in term of charisma, range of emotion and stature, but I need to see them in a live action role to be sure of their real acting skills.
Vico Ortiz
Definitly has the range for Bonchan and the friendly aspect too... maybe too friendly. We would need to see how they do in bad mode.
Terry hu
They seems to have the range of emotion but look a tiny bit young and seems too friendly (although this might play in favor of Bon Chan). With a good training, they could do very well (Imagine Sanji is complete distress in front of this beautiful actor... and who wouldn't know what to think, I think that it could be hilarious)
It would be a bold choice as Bon Chan looks more masculine that they looks feminine but I'm not against that type of change
Mason Alexander Park
My current crush for the role of Bon Chan. They would be absolutely perfect. We would need to check if their comedic range is there but they are on point in all other aspects.
My finger is currently pointed at Mason Alexander Park for Bon Chan with a hearth on J. Harrison Ghee.