No I don't believe they are, those are the tasks/functions that taskeng.exe carries out, but it carries out some or all of those tasks on behalf of what ever created the scheduled task.
That is why I mentioned the only process that I know which might create a scheduled task that would have a large string of letters and numbers is the avast emergency update function.
There is an avast emergency update entry in the Task Scheduler - that runs to check if there is an emergency update available - if one is available then it creates another task schedule to handle the update. Once that update is done, this task schedule would be removed.
But virtually every answer given is a bit speculative as in all honesty, there is insufficient detailed information to say what is responsible when the general information is lacking in detail.
taskeng.exe Task Scheduler Engine taskeng.exe {long string of letters/numbers}
If you notice it again I suggest that you do a screenshot of it.
What has been mentioned before use WinPatrol as it can get more detailed information on scheduled tasks than might be available with how your trying to find out, see example image