In answer to your questions:
1) There is a filter option available in the sidebar by default as seen on the
JobRoller demo site where you can "Browse by" Type, Category, Salary and Date Posted. Changing the actual searchbar at the top would require customization on your part as there aren't configurable options for this in the JobRoller admin.
2) There aren't any existing plugins in our marketplace which offer this functionality as described, so currently it would require customization on your part if you were looking to add a review feature to the theme. AppThemes doesn't offer customization services, however we do have a
certified partners page where you can find developers for hire who are experienced at working with our themes. Thanks.