Regarding Caitlan's children born in captivity-- a competent attorney, either in Canada or the U.S., will be able to begin to establish identity and citizenship documentation for the children pretty rapidly. Within days to weeks of their arrival. Their situation, and that of their parents, has been so well documented for so long, that this identification documentation process will, IMO, move rather smoothly. I think they will likely have dual Canadian/ US citizenship. That will give them, and Caitlan, lots of flexibility as to moving across the border, if or when Caitlan wants to do so.
I think Joshua Boyle likely has limits on his ability to freely enter the U.S. because of his behavior, ties, and previous history.
No links, but my common sense informs me that Joshua Boyle will likely be under very close observation/ monitoring, and scrutiny, for many years by both Canadian and U.S. authorities. I don't think it's impossible that he will eventually face some serious charges. This isn't a case of mere immature stupidity/ hubris/ naviete (like Lindhout and Saberi, IMO).
I wish Caitlan would leave him, but I doubt she will.
Not sure if this was posted-- didn't see it earlier in the thread. Press release statement from U.S. SOS Tillerson from Oct 12. It is interestingly "non committal" toward JB and CC, and instead praises diplomatic relationships. Really-- not a single word of support or praise toward CC/ JB, or even that they were grateful or welcomed home. It is what is not said, IMO, that is revealing. Some might say that is typical for a SOS release, but IMO,it is very linguistically stark in its comments on the rescued hostages, who are typically referred to in slightly more diplomatically sympathetic and warm words. For example, only that they are "safe and secure". I understand not criticizing in any way the Pakistani government, but it is odd/ revealing that the hostages are minimized almost as objects, not a family with small children.
https://www.state.gov/secretary/remarks/2017/10/274751.htm