I think Jaz will be able to prove Harry is a traitor.
If Evie gets banished because she is the last remaining one who "didn't know about the shield". She's faithful. So Ross was the only traitor amongst the 3, but because Jasmine has since been murdered, there must be another traitor. Therefore the shield thing was false and Harry must be a traitor and it must have been a recruitment not a murder.
He has to convince Molly though. But he does have cast iron evidence as above. Convince Molly, and Andrew will obviously be convinced too.
But unless Molly and Jaz then turn on Andrew, Andrew wins. There is suspicion about him though.
Evie could obviously also work it out now. Her plus Jaz plus Andrew could get rid of Harry. Then Evie, Jaz and Molly have to get rid of Andrew.