Dear Patrick,
Following are the observations on on
www.dev3.keylost.ca/fr/
1. Mistake in your Modules:
You need to add classes only in the Module Class Suffix
e.g. animated fadeIn eds-on-scroll
but you have added: gtm_astu class=" animated fadeIn eds-on-scroll
And as far as I can tell, this is on all your modules with animations.
Please see this screenshot for more info: adobe.ly/2gbiLTp
2. Homepage Screenshot on Various Browsers:
IE11, Firefox 56.0 (64-bit), and Chrome Version 61.0.3163.100
And since you're not satisfied with the answer provided previously.
Please take a look at the screen-cast here: adobe.ly/2gc8Jl1
3. So Called Plugin Conflicts:
Now coming to the Console Errors you received.
As you can see in the screencast provided above, these files are
MISSING from your template folder, "gtm_template2/css"
I am sure you understand 404 is a File not Found error. and as far as my experience goes,
have nothing to do with any of the Plugins/Components installed.
Now, like I said before, Please let me know if I am missing anything.