Hey Robert,
Thanks for reaching out. Upgrading to PRO will not provide you with options to pull of the customizations you are trying to achieve, and even with a premium license, we cannot assist with any custom coding projects.
Check out this article to learn more about the support policy and what comes with license support → https://theeventscalendar.com/knowledgebase/what-support-is-provided-for-license-holders/
So the best way to pull off the customizations you describe is to start tinkering with custom theme files. You do NOT have to modify core plugin files for this—you instead basically make duplicate versions of plugin files and put them in your theme, and then you can customize THESE duplicate files.
As noted, we cannot help with this process in terms of support, but we’ve written quite a bit about how to customize in this way.
The first thing to read is our Themer’s Guide here → https://theeventscalendar.com/knowledgebase/themers-guide/
Check that out, check out any of the other articles linked from it, and research online anything PHP or WordPress-related that you’re not familiar with. With these tools and some tinkering you’ll can pull off pretty much anything.
I hope this information helps!
George