I’m not sure why you think these Muslims are the ones Australia has asked the US to accept. Maybe I’m wrong, but I’m getting the feeling that because you know there are Muslims on Manus and Nauru, you are assuming that that is who we are talking about here.
There are also a significant number of Christians refugees in both places, and as I’ve said, I’m fairly sure they are the ones Australia has asked the US to take some of. That’s the only thing that really makes sense to me. Australia wants the US to take some of these people and will have asked the US to take the ones most attractive to the US - not the ones the US is most likely to say no to.
And I really can’t see President Trump continuing to support the agreement under any other circumstances.
I have put in a call to Team Trump to see if we can confirm.