Days out from the Kiwis' squad being named for the tournament, Taumalolo made the shock decision to pledge allegiance to Tonga rather than his country of birth, neglecting to inform New Zealand officials along the way, leading to accusations of cowardice from both Kidwell and Kiwis captain Adam Blair.
But following Saturday's historic 28-22 victory over New Zealand, Taumalolo revealed regret at the way the situation played out.
"I definitely could have handled it a lot better to be honest, that was probably the biggest [regret]," Taumalolo said.
"I spoke to [Kidwell] after the game and we exchanged a few words. I apologised about how things went and he was pretty good to talk to, he said how happy he was for me to represent my country of heritage and said good luck.
"'Kiddy' has been a great coach for New Zealand at the World Cup and I just wish him all the best for the rest of the World Cup."
Taumalolo cited his role in the North Queensland Cowboys' surprise charge to the NRL Telstra Premiership Grand Final as a key reason for him not informing the New Zealand Rugby League of his decision.
"Obviously the timing was one of [the things I could have done better], I thought it was fair enough on my behalf, obviously the timing of it was a bit late but I didn't want to distract my preparation leading into finals footy for the Cowboys," Taumalolo said.
"Post-season celebrations were probably one of the reasons why I had to make my decision [then] and obviously teams were being finalised."
While Saturday night's match against the Kiwis at Waikato Stadium won't go down as one of Taumalolo's best, he played a vital role in handing Tonga the advantage in a torrid middle battle.
The 24-year-old lock carried the ball 14 times for 163 metres, along with making 21 tackles, and was at the forefront as his side started to overcome New Zealand in a second half where they scored five tries.
While his immediate focus will be on Tonga's march towards more history at the World Cup, which begins with a quarter-final against Lebanon in Christchurch next week, Taumalolo remained coy on whether or not he would ever wear a Kiwi jersey again.
"I haven't thought too far ahead. I think I will take it as it comes," he said.
"There will be a lot of big decisions made on my international career, whether I play for New Zealand or not ever again, and whether I play for Tonga again."