the number of days since the lead owner's last activity.
The first five columns can all be obtained from the Lead object, and last column from the Lead Task object. So we create a multi-step report as follows.
The first step produces the Lead Owner and the total number of leads for that owner.
Steps 3 and 4 are similar to step 2, except that they use different filter settings: Status = Working and Status = Closed, respectively.
Step 5 produces the date of the most recent task created by the Lead Owner, and that value is obtained from the Lead Task object.