Did you actually watch Couture v Belfort 2?
All three of the MMA fights between Couture and Belfort were so many years ago that I can barely remember them.
If memory serves, someone who was in some type of corner accidentally overlooked one of the wrapping tapes on one of the MMA gloves.
As Couture advanced in order to initiate a clinch, Belfort wanted to punch him and Belfort's stray wrapping tape just so happened to graze one of Couture's eyes and made a considerable cut. Yes, the doctors and everyone else stopped the MMA fight and decided that it was a TKO (Cut).
Nowadays, we know that Couture is 2-1 against Belfort. It seems like you're implying that St-Pierre vs. Serra 1 at UFC 69 was way closer to an actual win for Serra. If that is what you are implying, I would agree with you.
In the year 2007, Serra repeatedly caught St-Pierre and he kept damaging him until he forced the referee to stop the MMA fight. Obviously, everyone on Sherdog has seen the infamous gif of St-Pierre admitting that he got caught by tapping out at the exact same second that the referee started to sprint into the fray.
In MMA fights and Boxing fights, there's always the risk of controversial decisions. Many of the fans of Nathan Diaz think that it's controversial that the doctors and the New York State Athletic Commission stopped the MMA fight between Jorge Masvidal and Nathan Diaz.
Many of the fans of Nathan Diaz say that he always turns up the heat in Round 3, Round 4, and Round 5 (especially the latter two). Regardless, the MMA fight was stopped and it was decided that Masvidal won the encounter and the UFC BMF Championship (for whatever that's worth).
In conclusion, I would say yes, I consider Vitor Belfort to be the former UFC Light Heavyweight World Champion (with 0 title defences).
I also consider St-Pierre to be 1-1 against Serra.
Furthermore, I consider Jorge Masvidal to be 1-0 against Nathan Diaz.