Don't delete tickets after sales start. Instead, make it private to hide it from the public.
We have some pre-made questions that guests can answer when they register. You can find them under "Attendee Information to Collect." If you want to ask your own questions, go to the Data Collection page and make your own questions. Then just choose which ones you want under "Attendee Information to Collect" from the Event Edit page.
Please make sure to collect the Attendee Name and Attendee Email for all events.