Wasn't Harry really odd for being able to possess people?
Not when he first jumped into Mort and threw up a shield he didn't, he did get booted out within a few seconds though.
Not especially? I thought the reason he got Mort was he was too terrified to respond, plus having experience with such things he knew what Harry could do, survival instinct, well training anyway.
I'm not sure Mort can draw them in.
Mort does draw them in iirc, specifically. Then sir stuart talks about he thought Mort forgot how to do that, implying it was intentional and probably more complex then simple spirit commanding.