My comments are under parenthesis.
When working on PriPara’s arcade game and recalculating the budget, they realized it wasn’t enough for the number of characters they had to make. Especially, they would be one character short in comparison to their business rivals. (Aikatsu! etc)
So they decided to recycle Faaruru’s old model and palette swap it to make a new character, who would be either her clone or sister, they didn’t decide yet.
Faruru during PP s1, Garuru with Mikan and Aroma as Garomagedon, Faruru post S1.
In contrast to Faruru, they decided to make Garuru into a Vocal Doll born from negatives feelings like frustrations and complexes. They weren’t sure on how to introduce her, as just randomly bringing her in wouldn’t make her a sympathetic character. So they went with a bold move, temporarily removing Faruru from the anime and arcade game at the end of s1, and as it was around the time the summer vacation battles among PriPara and its competitors started, it was the perfect occasion to introduce the small and rampaging Garuru. (Is this part of the real reason why Faruru left the anime at the end of PP S1? Because she had no reason to leave after what happened in that episode and it was incredibly stupid. Though that was nothing compared to some of the things that happen in S2).
Starting with her live debut, Garuru would develop and slowly earn the audience and players’ affection. They wanted Garuru to be an idol who can only do one-tenth of another idol’s performance, and by trying ten times harder. That it’d be very difficult for her to keep up, but that she wouldn’t give up, and evolve at her own pace. They wanted to teach little girls to never give up, to always try their best even if they suck and to never forget having fun. Garuru’s introduced in s2 of the anime/game, because compared to Laala and co’s developments at that time, her perspectives are much smaller, making it easier for little girls to relate to her. (This is ironic, as I consider S2’s part of the plot about these themes pretty badly handled.)
The fact that Garuru is rebellious, doesn’t say the truth, and bites people, is used as gags, but it’s also a way to demonstrate she yearns for attention and human contact.
The rest of the story is as you’ve seen in the anime and game, and they managed to trigger Garuru’s debut at the best possible moment, after 6 months of planning. The only error they did was actually caring so much about Garuru and her background, so in the end, they used more money than they saved. And then she joins Aroma and Mikan to make Garumaggedon. OhbaP said that similar to this Garuru story, he’ll try to write about how he thinks Garumagedon was made and his personal anecdotes about it some another time.
This is pretty interesting because while I haven’t caught up on Idol Time PriPara yet, I know about Farara and Garara, so maybe they were also made as palette swaps to save money.