Has 'The Flash' Made Iris Immune From Harm?
Way back when The Flash began its first season, the pilot episode ended with a reveal that blew [...]
Not definitely...
While this is a legitimate question, the answer seems fairly simple at face value: given what we have seen so far on The Flash, simply restoring her byline does not guarantee Iris's safety.
Why not? Well, because her byline has been removed, replaced, or altered in the past and then restored, only to have things change again.
There is very little predestination in The Flash, partially because if there were major landmarks you knew would happen in a decade it would make things in the present much less urgent.
The use of time travel and the consistent weakening of the timestream likely means that, in-story, Iris is no more "safe" for the next seven years than she always was. Even if she was safe, for instance, what if something that one of Barry's many time-traveling villains did changed the history around her? Iris could be fine, she could be married to Barry, everything could be great -- and somebody could still blow up the newspaper office and obliterate the headline and its byline from history forever.
So, basically, it seems like there's no real reason to believe that much has changed, right?

...but almost certainly
...Well, yes and no.
First of all, there are pragmatic elements to consider, and storytelling elements, too. After spending much of season 3 trying to save Iris from certain doom, using that as a major storytelling device again right away would feel pretty redundant, and would also run the risk of making Iris feel too much like a damsel in distress.
Since a big part of Iris's appeal is that she's a badass who can take care of herself, endangering her once is a subversion of expectations and a potentially interesting idea. Doing it too often, or doing it twice in close proximity to one another, runs the risk of harming her character.
Another thing: while we just talked about how the drama on The Flash is somewhat diminisihed if there are too many certainties in the future, the show has given some indications that they may be embracing a bit of certainty.
After all, last season people from the future referenced The Thinker, a character who will play a major role (as the season's big bad) this time around.
The lighter tone and "more fun" that has been consistently teased about season 4 might also play a part there: the ever-looming specter of death is less important as a plot device if the tone and feel of your show implicitly tells the audience that major characters cannot or will not die.
Of course, at the end of the day, there is one certainty: as long as Iris's name remains on that byline, we know she's fine. At the moment it seems very unlikely that the show will be revisiting that idea, so while she does not have plot armor in the technical sense, it seems likely that she does for all intents and purposes.
