Uvo would win of course but I wonder if Rock is not stronger than BBI. Saying that Transformed Gon is in Netero league is underestimating him. Pitou said he has the level of Meruem and Netero is not in Meruem's league, even his strongest attack didn't really affect him. It means Gon is at least stronger than him and personally I think he was stronger. Before the Rose explosion, Meruem was just a HtH fighter, his ability was not really useful in fighting. He could have damaged Gon but I don't see how he could have won this, transformed Gon is physically stronger than Meruem because he is an Enhancer and also because his kick made Pitou bleed, even Meruem tail whip(with killing intent) didn't hurt her like that. With Jajanken combination he could have been way more dangerous too. I don't think super Gon was equal to Netero either, it's said he used all his potential and Gon is a genius among geniuses but it's debatable.
The three major factors in a Nen battle are:
1-Your aura volume.
2-The quality of your Hatsu( with conditions etc).
3-Your aura control( which is refined with basic training).
Aura volume is basically your strength and Netero is not in the in the same league as the RG, Colt confirmed this. But he can compete Pitou because his Hatsu is way better, a fight against Pitou would be similar to his fight against Meruem except Pitou is not as durable, physically strong and fast as Meruem, she can also heal herself, Meruem can't do that and with Doctor Blythe she won't be slapped like Meruem. In a fight between those 2, Pitou is more likely to win, she can charge forward like Meruem and in case she is hurt she could keep her distance and heal herself, and she is more than capable to take a Zero because she survived Gon's Rock( who is way stronger than Netero, that Rock attack was the strongest attack used by an human so far, and she can fight even when killed).
A fight with Pouf would be even more complicated because of Beelzebub and his scales. And I don't see Netero win against Yupi, seriously.
I think Netero couldn't beat the RG but he is more likely to win Pitou among those 3( he would lose though), if Meruem had a better Hatsu their fight would have been even more one-sided.