Hey Jennifer,
Thanks for reaching out!
You can customize a few, specific colors with the Theme Customizer. To see a full list of the support colors there, check out this knowledgebase post → https://theeventscalendar.com/knowledgebase/pro-color-customizer/
For anything other than the specific few options in that list, though, you would have to write custom CSS on your site to make a customization, whether it’s just a color change or something else. We cannot help with writing custom CSS, so just to be clear, if you were to purchase a full license you would still have to write any CSS customizations on your own.
As for conflicts with WooCommerce, there are no known conflicts at this time. We make some add-ons that work explicitly with WooCommerce, in fact, so we strive to have no issues at all with it. And at present, there are no known issues.
Cheers!
George