Ok guys, did some testing so here it goes:
1. The app window (in any config) did not show up on Enable Cart Page or Enable Order Confirmation Pages.
2. The app also did not show up on Main pages (using Shopify's default Supply theme)
3. There are no Google Font Library customisations, so it makes impossible to adjust it uniformly to Branding standards in terms of Font.
The app needs more work, the idea is there, but the functionality is not there yet. I hope you can develop it more properly for our use, thank you.
Thank you very much for taking the time to leave a detailed review. We'll improve our app based on customer's feedback. Definitely will implement those missing features you reported ASAP.