I have written for ISIS magazine in the past and occasionally still do. I can assure you that ISIS is not an official magazine sanctioned by Bob Dylan's management. It was started by fans and is still run by fans. That said, if Bob Dylan's management wanted to be difficult about its content, they probably could - but they don't. They are aware of the magazine and, for all I know, read it. There is no equivalent of TK in Dylan World - and I do know TK.
Now, in terms of Dylan news, as published on their website, they do not put out stuff just because they can but because they think it is correct and the timing is appropriate. They have a very high success rate in terms of accuracy - approaching 100%, I'd say. I know this because I have myself provided information to them for publication, based on the sources I have built up over the years. They also have sources of their own. I have had a pretty close working relationship with the ISIS people for over 20 years and, indeed, only a month ago, attended an entirely social event in the north of England, sharing a table with them and some of the old-stagers in Dylan World. Some of you may or may not know the My Back Pages people, also fans, who ran a Dylan book service in their spare time, put on Bob Dylan conventions and also showed videos from here, there and everywhere.
Getting "unknown" news is not always a straightforward process. One tries to triangulate information - that is, get it from three independent sources, who do not know one another. This is increasingly difficult in the internet age, where you can appear to get something from different dources but it is simply one source whose bit of information has been passed around. Sometimes, I have got a snippet of information on the basis that it will not be made public unless it also comes from someone else. I have always honoured that, even if it means being a bit behind with its publc dissemination. This is the proper course of action for a number of reasons: (1) it is the honourable thing to do, (2) it safeguards the source for the future, as well as increasing your own credibility as someone to whom "secrets" can be entrusted, (3) it helps identify which other sources you should approach and (4) it helps to assess any other rumours that may be picked up on the same subject. I believe the people at ISIS are similarly honourable and careful.
If ISIS says that shows are "being talked about for North America", in the context of Dylan and Knopfler touring together, then I would believe them. They will not be talking about fan chatter alone. If they were, they would make that clear. What they say is consistent with my own view and my own sources. It is not certain that there will be any such BD-MK tour later this year but there are indications that this could happen.
How this would fit in with any MK solo tour, I do not know.