Object pronouns with the Imperative

Originally Posted by fglorca (Post 148809)

Are the following sets of plural imperatives correct (the direct object pronoun 'lo' replaces 'el libro'):

Buy it / Don't buy it:
Compradlo / No lo compréis (informal)
Cómprenlo / No lo compren (formal)

Buy it for me / Don't buy it for me:
Comprádmelo / No me lo compréis (informal)
Cómprenmelo / No me lo compren (formal)

Thank you.