So basically you just need events (with tickets) on the upcoming events list to link to the single event page, but without those buttons/links being present on the single event page itself?
Currently I don’t believe there is a template tag to easily detect if there are WooTickets tickets assigned to an event, but you could definitely add your own. Then you could do something like this within your custom list.php template (and style it appropriately to make it button like if that’s what you need).
Does that help at all?