I once bought a trio of geckos, and I currently keep two trios, so let me explain.
The first trio I bought (from someone local who was being deployed) was a disaster. One of the females was clearly the alpha and beat up the other female pretty bad. It didn't take too long before I split them up and isolated the female who was getting the short end of the stick. I tried to re-introduce that female a while later, and once again, the dominant female beat her up and she had to be removed.
As crazy as it sounds, over the years, I would say that female chahoua are meaner and more aggressive towards each other than male chahoua. Sometimes during mass cage cleanings, or just having out a few geckos at a time, I've seen females go after each other in a fairly aggressive manner. Males never seem to really care about the presence of another male, but I also don't leave them together unsupervised. Some ladies will bite each others legs, feet, tails, etc.
Because I'm short on males, I started experimenting with trios last year and had a decent bit of success. I think the ability for this idea to work hinges upon the personalities of the females involved. I have a handful of females who I know are very dominant and could never be in trios - these are the ladies who will go after their female friends in passing if given the opportunity. However, I have other females who are easier going, less dominant and more compatible with other females. My trios are comprised of such females.
Starting trios together definitely takes a lot of careful supervision, but I've had one that's been together for two seasons with no problems, and another that has been together since ~November 2018 with no problems.
My personal preference is for 1.1 pairs so that I can maximize the number of unrelated offspring I produce in a year, but with a shortage of males... or just because you want to try it, I think this idea CAN work as described above
Great topic!