I have had a bit of experience with the yellow labs (about 4 years). I rescued a 3" male yellow lab about a year ago from a tank with several larger fish including a fully grown, very mean blood parrot, a fully grown tiger Oscar, a pretty aggressive, fully grown, male yellow lab, and several red jewels (amongst others). I also saved a smaller red jewel who was being bullied.
We call this guy Yellow. I know it is not very original... But that is his name. Yellow has not had the easiest life, needless to say. He is a scrapper, and he had lost sight in his right eye before I saved him. He is a fighter though. Whenever the red jewel matured he started fighting with Yellow. Yellow held his ground and they maintained a more or less peaceful relationship after that, sharing the tank.
The red jewel had to be re homed due to his excessively aggressive nature after adding some electric blue mainganos to the tank. Eventually, we added 2 more yellow lab females and more female electric blues to the tank. Yellow was thriving. No aggression. But yellow was the boss.
After relocating an aggressive red devil to my African tank due to him beating up on my South and central Americans, Yellow has taken on a more submissive role. He tends to stay in "his" cave 70% of the day. He does still come around and interact though. He still has his own personality and comes up to eat and loved the blood worms that I gave him today.
I say all this to say that in my opinion yellow labs have plenty of personality. It may not be the most dominant or aggressive if placed in a tank with more aggressive fish. But when Yellow was with the electric blues and other yellow labs, he was really interesting to watch and displayed a lot of personality.