Hi Damein, the plugin will hide everything that is inside a div with class “fancybox-hidden”.
So if you switch to the Text view tab in the post editor and wrap your inline content like this:
<div class="fancybox-hidden">
<div id="fancyboxID-1" class="hentry" style="width:460px;max-width:100%;">
...inline content here...
</div>
</div>
Now the inline content (div with ID fancyboxID-1) will now be hidden and only show inside the light box.
Note: do not give the inline content div itself the class fancybox-hidden because then it will also be hidden inside the light box too.