This post gives you the options of choosing the appropriate leveled character for your Encounters season.
For level 1 characters please visit the following:
Level 1 pre-generated characters: PDF here (3.5 MB zip)
Level 2 pre-generated characters: PDF here
Level 3 pre-generated characters: PDF here
You can also visit Dungeon's Master to download their level 1 characters from heroes of shadow here and the level 3 are here.
It has been frustrating to redo and replay characters from 1st level. I find it would be that much more frustrating for the regular players at my table to restart at the bottom rung every few weeks. In all my career as a player or DM, I have never started so much from first level as Encounters. Sometimes it is not enjoyable to restart all the time. There is nothing that give me(personally) more pride than to watch my character flourish through the levels. I find that players get attached to their characters and begin to develop them as the time goes by and to see that crushed every few levels is disheartening for them and DMs at the same time.
So go out, have fun and play strong. Above are all te resources you would need to enjoy your time at the table during sessions of Encounters.