They could have done competitions based on each youtuber channel theme: Harley jewstein would be against other cooking youtubers in a cooking competition, minecraft youtubers would be on a minecraft hunger game type tournament, hotdog competition for the mukbang channels, you could even do a funny figthing event like those guys that use armors and swords with youtubers that talk about medieval shit and are probably into that, hell you can even reserve the boxing for people hated by the world wide comunity and that are desperate for clout, and style it into some form of collisseum where no matter who wins you get to see both beat the shit out of eachother for your sick entertainment like the Wings vs Boogie boxing event, no need to risk head injury.
You can craft fake, corny and over the top beefs like the WWE between the figthers, have them do like 5 videos or something talking shit about eachother and then continue on twitter until the grand event, idk why hes even considering paying for publicity when this is a fucking youtube event, just do videos about it, is free, Froggy (fresh) had the right mentality about how to promote this shit.