5. Simple means you could lose all the data between each full backup. So if you take a backup once per day, and you have a disaster right before the backup, you will lose everything back to the previous backup. Most production databases are in FULL recovery, with transaction log backups every 15 minutes or so, and a full backup nightly (many options depending on each situation).

Read about "recovery models" to get the details, and decide what your company needs for disaster recovery options.

7. Do you mean a 3rd party, such as a consultant manages your backups, or that you do backups, but use a 3rd party tool such as Redgate or Idera ?

9. Shrinking is usually a bad idea (hurts performance by fragmenting data) , unless you have an urgent need to recover space.

Plenty of detail on these topics if you search. Read up, then come back with specific questions.