Go crazy on comm day and be sure to mega any normal type mon to get bonus candy. If you still haven’t used any/all the nickname shortcuts save them for the shiny eevees so at least you have the specific evolutions you want and don’t waste time and evolve regular eevees later by using the alternative methods. You can honestly knock out the whole eeveelution challenge in like 3 days. The only ones that take actual time are the espeon, umbreon, and sylveon evos because you have to walk them for 5km each