finally got all of the 7 treasures! also only evolved my main characters once because i prefer how they look in the middle stage both visually and thematically. i also got up to the 3 star expert rank, missing only the guildmaster rank but i just don't have the patience to get all those points LOL
in terms of actual stuff to do, i didn't finish any of the Zero Isle challenges or recruit all the legendaries. optional fan challenges like recruiting every single pokémon and kecleon are too much for me so i won't even try
also: i never used wonder mail codes during my entire playthrough. i felt tempted, but chose not to :-)