Yeah, you can run a parallel event with a swith off, if it's a map event. However using a common event requires a switch for it to trigger. Just thought I'd get that out of the way.
Now if you want the events to set and not add anymore as the game starts. You can do 1 of 2 things.
1.(Read this if your good with conditinal branches)
Make a Common event that sets all the values at the start, by making it Auto start, name your switch, then insert a conditional branch. Make the conditional branch state, that if this switch is on, set values to this. After you place in all your values place in switch off for the auto event. You should be able then toggle this command via F9 in the games debug mode. After making the event in common events, go to your map, make an event make sure it's auto start, and have that start the common event. Also be sure the common event switches off the map event. So you'll go back to your common event and place in the switch off map event switch. Or for the map event you can use a self switch to switch off the value switch.
2.(your other idea)
Create a map event which is set to auto at the start, and have that set the values for you, then after you can place in anything you want happening after it. Of course you'd want to create another page to stop it all, or you'll have a looping auto event.