Hi Dante,
Is it possible to customize the WooTickets that the ticket includes a TShirt (for example). If a customer purchased 5 tickets they can tell a person’s name and shirt size?
That is certainly possible – however it’s not something you are likely to be able to do using just The Events Calendar, WooCommerce Tickets (or “WooTickets”) and WooCommerce itself out-of-the-box.
Possibly there may be an existing WooCommerce extension you could buy and install that may get you even closer to what you want here (definitely take a moment to review the available addons over on the WooThemes site) but I suspect some programming and WooCommerce development know-how would be needed here.
Additionally do you have to have the PRO version of The Event Calendar to run WooTickets?
No, just the core The Events Calendar plugin plus WooCommerce itself. You can certainly use Events Calendar PRO in addition to those but it is not required.