for first issue better not use a data folder, instead create a custom grf and load it from data.ini (use grf editor it will make sure the encoding in the grf is correct)
second what description? if you mean the text in client its either texture files or msgstringtable you need to use a translated bersion of those
third https://github.com/Asheraf/Translation/blob/master/System/itemInfo_Sak.lub but notice that you need to change the functions at the end of the file unless you're using latest version of RE clients