Thanks for the links.
I think at some point you have to say that in 18-24 months, you're going to be able to dig up all the info you possibly can, even with regards to Syrians specifically and other groups where it is difficult to find information. It's just a risk you have to be willing to take.
And so far, post 9/11, 750,000 or so refugees have been allowed into America. Not one terrorist act committed, and apparently only 2 out of 750,000 have even been arrested for association to terrorist groups.
I'd say your odds are pretty good with regards to 10,000 refugees. I know you aren't saying stop the process, but lengthening it any further or delaying it means that America is basically saying no. People can't live in refugee camps forever.