Hey Andy and welcome to the forums!
Yes, custom registration fields is definitely possible in Event Tickets Plus. That will allow you to create fields for users to complete for each ticket they purchase.
And, yes, there is an option to export and download the information for all the attendees of your events into a CSV file, including the information they completed in the custom registration fields. Here is more info on how that works.
Does this help answer your questions? Please let me know. 🙂
Cheers!
Geoff