Documenting SSRS and SSIS jobs that are the Job Activity Monitor
This simple query on MSDB should get you started:

SELECT s2.subsystem AS [TypeOfJobStep]-- when subsystem = 'SSIS' then 'SSIS job step'
     , s2.command AS [JobStepCommand]
      , s.name AS [JobName]
FROM dbo.sysjobs AS s
JOIN dbo.sysjobsteps AS s2 ON s2.job_id = s.job_id


You can identify SSRS subscriptions because their name will be alternating alphanumeric strings with dashes. I think a SUBSTRING function could determine that.

SSIS job steps should show subsystem = 'SSIS', depending on how you execute your SSIS jobs.

As for identifying which tables your SSRS jobs hit, that will require you to document your SSRS reports. SSRS reports can access data through a stored procedure, or through an embedded query within the report. Once you determine which they are doing, you'll need to determine a way to link them to the jobs you previously queried. 

This is the hard part, because SSRS reports can use multiple data sources and those data sources don't have to be on the same SQL server as your scheduled jobs. I don't know if this part is feasible.