Hey Jmiller, Just wanted to jump in here and confirm a few things.
From your screen shots the admin bar is not visible while the modals are hidden. On top of that the space is there for the admin bar as it should be in your images above. This tells me that the large bg image you have is actually being layered over top of the admin bar.
Couple of facts about our plugin.
* We target only our modals with prefixed classes so there is no way it is a CSS issue in the plugin.
* Our JS targets specific elements all contained inside the modals for styling, and has no functionality that would target or change the admin bar in any way.
Our modals default to z-index of 999, and the wp-admin bar uses 99999 and will display above the modal and overlay by default.
The issue is definitely in your themes CSS and in reality a theme should never use z-index that high. Typically your theme should never need to be z-indexed above 100 much less 100000.
You issues are all related to the fact that you are essentially layering your background and header above everything else. I can’t tell you exactly what needs to be changed as I can’t log in and display the admin bar, but you should search your themes style sheet and consider changing the z-indexes to lower values in the 0-100 range.
If you would like me to troubleshoot this further, I would need some temporary admin credentials – feel free to email me at danieliser at wizardinternetsolutions . com
Last note: The reason the WP admin bar uses 999999 as a z-index is because they assume nothing else would be set higher than that, portions of your theme are set at that and higher.
Also, if you look at Foundation or Bootstrap modals, they also use the standard of 998-1000 for their modals.
A quick Google search yielded a couple of useful articles regarding z-index and using it properly:
https://www.impressivewebs.com/a-detailed-look-at-the-z-index-css-property/
https://www.smashingmagazine.com/2009/09/15/the-z-index-css-property-a-comprehensive-look/