is this turn based? or is it running in the background all the time?
if its turn based you wouldnt have to set a timer just run each event in order and wait for them to finish or raise an event for the next task.
if this is to run every x minutes or seconds in the game, then only 1 timer is needed. Set the time to the amount of time for the first update. Each task run when they receive a completed event from the task before. after the final task, reset your timer.
now if this is inside a blueprint it will run async from the main game and control itself, you would need to know how long a task takes as it wont start til triggered by previous task finishing. maybe an enum state that each task waits for as an alternative?