I doubt it. Simply because no one is interested. Memcoins in the crypto community are perceived solely as a way to get rich quick. There is no other merit to these cryptocurrencies. No one is trying to look for some kind of utility, useful functions in them, or to create large communities. The whole idea of creating memcoins revolves around greed and lust for enrichment. This is why I believe that memcoins will not unite into anything.
What if we don't just casually rule out the possibility of this unification? By default, I am of the same opinion as you but then I did a quick research about the project OP mentioned MEMEVENGERS proposing this unification and I can see that It just got its token MMVG listed and Bitget is hosting a deposit/hodl event to split 85M MMVG in commemoration of the listing. This brings me to the realisation that this idea of memecoin unification has gone past just a mere idea and is already being implemented. What if....just what if from this one project memecoins evolves into something better than what we have known all along?