My apologies, but these queries seem very easy to solve on your own just by reading the documentation or by googling
Anyway, because I'm in a good mood, here are some answers:
2. No, Tableau Prep only writes away to csv or Tableau Extracts
3. Obviously this will depend on what kind of business logic...
4. Tableau prep is not a report bursting tool and does not create Excel files.
Thanks Martijn for your fast reply.