Hey Giorgio and thanks for getting in touch! I hope our system will be a good fit for your project.
Yes, each ticket can be given a unique ID. There is a field where you can add the number (screenshot). And, yes, you can set the start and end sale dates for each ticket and make those dates independent of the the event date itself.
Event Tickets Plus does not support custom notes during checkout (though we are working on it). However, WooCommerce does have an “Additional Information” section at checkout (screensnhot) where that could happen.
Does this help answer your questions? Please let me know. 🙂
Cheers!
Geoff