Translation - Turks-Spaans - Sevgili arkadaşlar, sizlerle tanıştığım için çok...

Hola cheesecake,

Has elegido la segunda persona del plural para conjugar los verbos, sin embargo esto suenaría bien sólo en España. En los demás países de habla hispánica se usaría "ustedes" en vez de "vosotros" Lo que daría:

Queridos amigos,
Estoy muy feliz de conocelos. Qué bueno que hayan venido a Estambul y participado en Hayfemfest. Sus bailes, musicas, trajes y ustedes están muy bien. Nunca los olvidaré. ¡Hasta luego!
Saludos

¿Qué te parece?

Hola Lilian,

Thank you for the explanation But just one question; isn't "ustedes" used only for formal cases? Because in the Turkish text, he talks to his friends who are more than one ( So it is you-all in English) In this case, we can use "ustedes" for some informal cases such as this one as well, right?

Hum...that's something that has to be explained.

The singular forms have this distinction between formal and informal, but the plural form doesn't.
Sing you (informal) - tú (verb/2nd person singular)
Sing you (formal) - usted (verb/3rd person singular)
Plural you (formal and informal) - ustedes (verb/3rd person plural) (vosotros (2nd person plural/ used only in Spain)

Tú eres
Usted es
Vosotros sois
Ustedes son

I have mistaken as it is only used in Spain, I didn't know this. Thank you very much for the explanations