If Chloe goes then the ratings will tank. And the show runners KNOW this. It was why they pulled out the stops to get her back for this season. That is the talks you all have been referring to. They just barely managed to get her back for THIS season. No one has even mentioned as being in negotiations for next season aside from Tom Welling. And I would have thought that there would be options in Mack's contract that she will continue on with the role should the show continue past season eight, as it will now be doing. Since, aside from Welling, she is the only remaining original cast member, a fan favorite, and a character they created themselves so they don't have DC saying what they can and cannot do with her. Plus, she's the female lead for the show and they can only use Lois for 13 episodes a season. Chloe may get put through a lot of crap over the remainder of the season, but she's not going anywhere.
Plus, most people in charge of fan favorite franchises are notorious for dropping literal hints. "Technically a show veteran" does NOT say Chloe. It says someone who has appeared on the show for more than just this season. A "long-running character" is a character who has run a long way. Plus, they haven't released the title of the episode yet. Why? If there is a Crisis, a Flash will die. It would reveal too much.