A l'hombre de nous
Restera toujours
Au nom de l'amour
Un gout d'eternite.
Au nom de notre amour
Une ombre va rester.

In our shadow
There will always remain
In the name of love
A taste of eternity.
In the name of our love
A shadow will remain.

In English, "stay" refers to a presence, as in, "Can I stay here tonight?" So "A shadow will stay" is not incorrect. However, "remain" has the additional meaning in English that what has stayed is something that has been left behind. So "remain" conveys the author's intention in a way that "stay" cannot.

C'est le blue des livres d'images
C'est tout ce que tu attends de moi
C'est tout ce qui j'attends do toi. (a typo here: should read "que,", not "qui")

It's the blue in storybooks.
It's everything you expect of me.
It's everything I expect of you.

In English, "storybooks" has a nostalgic meaning about the innocence of chiildhood that "picturebooks" does not have. And I would guess that the author of the song wished to imply innocence.

"Waiting" is a literal translation of "attendre." But in French "attendre" means more than that, and similarly, in English to convey that extra meaning we say, "What do you expect from me?" It has to do with the behaviors that we hope for in the people we love, which, I feel, is the author's intent. "Waiting' does not convey that.

A l'ombre de nous
Ne pourra fleurir
Aux jours a venir
Bien d'autre que beauté

In our shadow
Nothing will bloom
In the coming days
Other than beauty

The translation posted above has a double negative in it: "nothing won't bloom," that needs to be corrected. "Bien d'autre que" means "anything other than." The posted translation loses the emotional intensity of the idea that only beauty will remain, which is revealed toward the end of the song: the shadow is the shadow of the intense feeling of beauty that the lovers shared. That is the surprise of the song that the images lead up to.

C'est la passion, c'est le délire
It is passion, it is delirium

"Delire" is delirium, which is closer to ecstasy. Excitation can also refer to anxiety. It does not convey how the lovers were transported to a more beautiful world in the same way that delirium does.

Cette ombre de nous
Les mille soleils
D'un amour pareil
N'y pourront rien changer
Car des premiers soleils
Une ombre va rester.

This shadow of us
These thousand suns
Of the same love
We can never change
Because ever since the first suns
A shadow will remain.

In English "ever since" implies a strong continuity that began at the first moment. It has an emotional strength that "from" does not have.

C'est tout ce qui me survivra
Tout ce qui, a jamais, vivra...
A l'ombre de nous

It is ll that will survive me
All that will live forever
In our shadow.

Because the husband has died, "all that will follow me" is a little confusing.

In French one can transpose "a jamais" and "survivra." In English, although it is technically correct, it is a bit awkward to transpose single words.