Backfiring is not normal; should not happen, even just now and then.
Suggest you give Honda Customer Relations a call, and find a dealer who can properly diagnose and repair the mower for both the backfire and recoil retract issues. A new mower should not have either of these problems, and if they are determined to be factory defects, warranty should cover the needed repairs. Have the serial number off the back of the mower when you call, along with the name of the dealer you contacted.
American Honda Customer Relations
4900 Marconi Dr.
Alpharetta, GA 30005-8847
Tel: 770-497-6400
Fax: 678-339-2519
Mon. - Fri. 8:30 - 7:00 EST