You can solo it. The first two parts are super easy to solo as an invisible Hunter. Death singer and Croat are harder to solo but with two people they are very easy, even on hard. For crota two gally rockets takes him down on hard mode. I did it with a guy who had no mic this weekend. He had never used the sword so I had him be the swordbearer. Only took him like 4-5 tries to take crota down.