As we all know, Newt isn't the best at parsing human intentions but he is the sweetest of cinnamon rolls. Chances are he's not great at noticing when people are flirting with him. What I'd love to see is that after the battle with Grindelwald, Newt has a crowd of new admirers who are not exactly subtle about it. Newt on the other hand, is overjoyed that so many people are taking an interest in magical creatures.

Then Theseus arrives to see his little brother and he understands exactly what's going on. Thankfully, as they both grew up with a herd of Hippogriffs, Theseus also knows how to translate peoples flirting into something Newt can understand because he's a good big brother.

The people flirting with Newt can be whoever who want, I just want Theseus saying things like: "you saw that right there? that was them lowering their right wing almost to the ground and sweeping their left forward and up."