Boy: Salut!

(then they give kisses)

Girl: Ça va?

* Boy: Ça va bien. Merci! Et toi? (you don’t conjugate “va” because “ça” is the subject. The literal translation of comment ça va is ‘how is it going?’ You use ‘et toi’ which means ‘and you’ because it just sounds better. If you didn’t use it then you would have to say ‘comment ça va’ instead of just ‘ça va,’ and that sounds repetative.)

Girl: Comme-ci comme ça.

Boy: Joyeux anniversaire!

Girl: Merci!

Boy: À tout à l’heure.

Girl: Ciao!

Here is the two adults who don’t know each other:

Adult #1: Bonjour!

Adult #2: Bonjour!

Adult #1: Comment vous appelez-vous?

Adult #2: Je m’appelle _________.(I didn’t decided on names)

*Adult #2: Vous vous appelez comment? (awkward sentence structure – I suggest saying ‘comment vous appelez-vous’ again)

Adult #1: Je m’appelle__________.

Adult #2: Enchanté.

Adult #1: Comment allez-vous?

Adult #2: Je vais bien. Comment vas-tu?

Adult #1: Pas mal.

Adult #2: Au revoir.

Adult #1: Au revoir.

Not bad. It’s not perfect, but I can’t give you any other corrections that wouldn’t be more advanced than your current level of french. If I do it will sound like you used a translator.