Hi iuz!
Those warnings are from Redux, the framework I use for the options used in the plugin (and that last one is from WP itself). I’ve seen them before, and correct me if I’m wrong, but the plugin works regardless of the warnings, right? Or does it fail after it prints the warnings?
Thanks for reporting it, I have a pretty good idea of what’s going on, and I’ll see if I can get to the bottom of it ASAP. Cheers!