is it even possible to say :"saya menulis nama saya salah" ?
I wrote that. Duolingo graded it as correct.
It would throw native speakers off, but they should still get what you're trying to say.
Yes, but since "salah" is an adverb here it should come before the verb.
That has actually happened to me before. I was at imigration.
I wrongly wrote my name?
It's accepted now. It's what I put first time.