Honestly, it doesn't look like La Vie en Rose to me, like, at all. Especially if you listen to the medley they released this week, it's completely different.
Now, the visual/photos concept can resemble a little, but I think they may be trying to create a unique visual to the group, exactly because the group has a short lifetime? So, this way, people will remember in the future as "that group with a flowery visual, but with different music styles at the same time".
If you try to change the overall concept too much with this short lifetime, you may end up getting no attention at all, since it's harder to build a fandom if you experiment to much.