So for my Gith Battlemaster play through, I really did not need or want Laz'ael as a companion so I got her near the edge of the nautiloid and shoved her off.
Meeting Shadowheart as a Gith is a bit challenging. She really hates Gith and pretty easy to get it so she will not join you.
There is no encounter with the 2 Tieflings who would be guarding Laz'ael before the because she dead back in Avernus.
Overall, looks like Larian thought of most issue with killing Laz'ael early.
They actually planned that because once origin characters are released, you can play as her.
