I used Devin, Burnside, Luke, Laura, Alan, Jeff, Nick, Matt, Mikey, Andrew, Kayla, Forest, Dylan, Rick & Arietta all at max level and fully workshopped.
You can do Base I without repairs with Devin, Matt, Kayla and Air (Forest or Rick or Arietta ).
For Base II Devin and use all heroes whose DPS is more than 10K. (If you have maxed heroes you can do this without any repairs else free repairs)
For Base III Devin, Matt and Kayla are enough to do it without any repairs.
https://youtu.be/YwP4y2U6_H8
You can do Base I without repairs with Devin, Matt, Kayla and Air (Forest or Rick or Arietta ).
For Base II Devin and use all heroes whose DPS is more than 10K. (If you have maxed heroes you can do this without any repairs else free repairs)
For Base III Devin, Matt and Kayla are enough to do it without any repairs.