Re: khatam sharif
Reading the Quran anytime is recommended. Setting dates and special days for it, Soyam, Chaleeswan w/e is biddat indeed.
Reading Quran for your benefit is recommended, making Dua for the deceased is recommended. I dont think you can read for them, or make up for their accounts. Your accounts and deeds die with you 'cept for sadqah-ejariyah and the Duas from your family and friends.