I have never come across being asked for date of birth for buying an air ticket. As for names, since there is no direct transliteration between Thai script and our Roman alphabet there will only be an approximation of your Thai G/F name on the air ticket in our alphabet. Don't think it is a problem if there is one letter spelling difference from one flight to the next as long as it is near as dammit a sound-alike to her name on her ID card. I know my g/f's name has been spelt two or three different ways on various air tickets in the past.
