Designed by, but the idea is not his, he was told to do the set.
My personal issues are, that there is one man at the Lego group who is basically running it as his own personal MOC brand, with random ideas that don't necessarily translate to being great Lego ideas. I would highly doubt that these sets would see the light of day if another Lego employee suggested them. I know Lego can't please everyone, but there seems to be a growing issue that some ideas and themes never see the light of day (even with large fanbases behind them), but if he likes it (no matter how niche) there's a good chance it will be made into Lego.
It's like a football team that makes questionable decisions, you can trace it back to the management, and a change of management can cause a major turnaround.
Spice Girls is much more Lego friendly than a reality TV show (as the demographics for reality TV don't correlate with merchandise purchasers), but Lego Spice Girls is about 25 years too late (as all of the branded merchandise, like dolls etc came out in the 90s).
People are questioning who is coming up with these random (and typically poorly received) sets, and there is a clear answer. But people seem to get offended.
Lego Spice Girls, good idea, but 25 years too late.