Let's see what this tier is all about.
>This Metagame changes one very simple thing. It exchanges the highest and lowest Base Stats of a certain Pokemon. This causes many Pokemon to fulfill different niches and allows a lot of fun testing what are good new threats and what has been nerved to mediocrity.
As you can see, the only thing mentioned here are the Base Stats. For eg.- Azumarill's HP and Attack can be swapped.
But this has nothing to do with EVs and IVs, as they are not Base Stats, but rather built in factors that decide stats of a Pokemon at a particular level.
Hence, it is safe to assume that EVs and IVs are not swapped .
Hope I helped!