For what it’s worth, some publications have been focusing on the rumors about Maeve Foley more than those about Sophie Turner, and many industry commenters seem to believe that she is the more likely choice for the role.
There are various other rumors surrounding season 2 as well, though none of them are as prominent in the media as the ones above, so it’s probably an even worse idea to consider any of those additional rumors. In the end, a major production like this will always be followed by speculation leading up to a new release, and that’s a completely normal part of how the industry works.
We are likely going to get a little more information over the next few weeks/months, and fans will surely be waiting with a lot of excitement for any news about the show.
In any case, the new additions to the cast will be revealed one way or another. Even if the actress isn’t confirmed officially, all it takes is for one of her colleagues to slip and admit that she’s been involved in the production, and that’s all it would take for the rumor to start spreading. If the information is coming from someone actually involved with the show, that would obviously lend a lot more credibility to it than the random rumors we’re hearing now.