I don't think Stubbs is a host because why would Ford go through the trouble of having the host natives attack him when he could simply roll him back. I think Ford did that because he knew he was human and could be a threat once everything was revealed. Maeve was immediately able to identify that Bernard was a host and she reassured Felix on a couple of occasions he was indeed human.

He's definitely not a host. Maeve said so herself. Felix getting that information examines the very human element that exists within him. Considering he was never calculated and very compassionate throughout the show supports the notion he is indeed human.