Direct Questions

Hi, I have a few questions about some direct questions I’ve been translating into Greek:

Where are the ships going?
Ποι αι νηεs ερχονται;

  • Is this the correct verb to use in this situation or should I have used a more precise prefixed form?

Should I stay or should I go?

  • Wasn’t sure how to translate ‘should’ here?

Did you kill my brother or not?
ποτερον απεκτειναs τον εμον αδελφον η ου;

  • Did I translate ‘or not’ correctly here? And did I use the correct possessive pronoun in the right place?

Thanks for any help!