Because Fluttershy had to leave “The Squad” because of her having forced to be involved in various friendship-journeys. Most of these involves eX-members of Tree Hugger’s “environmental protection-army”, but some also involved ponies needing counselling after getting raped by Horse-Flies.
 
Lyra, bon Bon, Tootsie and Smash (I) went out to find new reqruits. While the rest of “The Squad” was trying to convince Shining Armor that King Sombra has changed for the better. Because he was convinced that he simultaneously casted a curse on Bright Mac and Pear Butter upon reviving them. Despite lacking evidence to support his claim.
 
After a while, the “Bon-crew” (a sub-group of “The Squad”) was approached by Zecora who showed interesst in joining. She was quickly accepted, then right after that she called upon two other individuals that also wanted to join in. Coco Pommel (who wanted to show the World that she isn’t a weakling. She did beat me (Smash) in a wrestling-match after all) and Ahuizotl (who gave up on trying to defeat Daring Doo, after he learned that she had published all of his humiliating defeats for the world to read. They were also accepted, I mean if King Sombra could be accepted, then so can Ahuizotl.
 
Even if Coco is a little scared of him, since she haven’t seen anything like him before today.  
So now “The Squad” has a total of 15 members and it most likley won’t get anymore unless someone leaves.
 
CREDITS:  
Lyra Heartstrings by moongazeponies  
Bon Bon by durpy  
Tootsie Flute by durpy  
Zecora by misterlolrus  
Coco Pommel by pixelkitties  
Ahuzotl by dashiesparkle  
Background by rainbowderp98