There is no need to wash utensils if it is kept in sealed plastic bags during the treatment. Surfaces of kitchen needs to be cleaned with soapy water.

No, it's not guaranteed, but a 3 months warranty is given.

Regular intervals of no more than twelve months. Shorter periods may be recommended, according to environment conditions.

Sprayed areas are of some concern while still wet. But once the carrier, which is water from the tap, has evaporated, the active constituent adheres to the surfaces and will not contaminate or harm you. Should you get in contact while it's still wet though, wash with soap and plenty of water as soon as possible