35:22 Nor are the living equal with the dead. God makes him hear who wants to hear. You cannot make the dead of heart hear just like those who are in the graves.
Offering prayers TO the dead is useless, since they are dead and cannot hear [mystics included] and also a sin since you are praying to rotten bones when you should be praying to Allah only! Offering prayers to Allah FOR the dead is also useless since Allah has decreed the following:-
35:18 And no person, being already burdened with his own doings, will be made to carry the burden of another. And if a laden one calls for help with his load, none may carry part of it even if he is a close relative. Hence, you can warn only those who understand their Lord’s Law of Requital knowing that even their actions done in secrecy have consequences. So, such people follow the Divine Commands closely. Whoever grows in virtue does so for the good of his ‘self’. And the destination of all is to God.
Allah does not reduce any sin, even with the help of relatives and does not say anywhere that He will lighten any sin even on Resurrection Day, but He will add to it those sins from others that you caused through misguiding them:-
16:25 They shall bear their burdens undiminished on the Resurrection Day, with part of the burdens of those whom they misled without this revealed knowledge. Ah, evil is what they bear!
It is useless to pray for living people:-
11:45 Noah called upon his Lord, "My Lord! My son was of my family and Your Promise is the True Promise and You are the Most Just of judges." [So, why was he not saved? Didn’t You promise to save my family?]
11:46 He (God) said, "O Noah! Your son was not of your family. For, his conduct was unrighteous. So, do not ask me of what you have no knowledge. I enlighten you so that you do not remain ignorant.” [You were not aware of the Divine Criterion of relationships which are based on Ideology and not on lineage otherwise you would not have asked such a question]
11:47 Noah said, “My Lord! I guard myself in Your shelter from asking favors which do not befit me, and for my lack of knowledge. Forgive me and shower me with Your Grace, otherwise I will become a loser.”
9:113 It is of no avail for the Prophet and the believers to ask forgiveness when the idolaters face the Law, even if they are their relatives, once it has been made clear that they are destined for Hell.
9:114 Abraham asked forgiveness for his father because of a promise that he had made. The promise was based on the hope that his father would mend his ways. When Abraham was sure that his father was a persistent opponent of God's Commands, he desisted from asking forgiveness for him. Abraham was kind-hearted, clement. [14:41, 19:47]
9:115 God never sends a folk astray after He has guided them, unless they violate the Laws that were made plain. Surely, God is the Knower of all things.
So this makes it even more useless to pray for dead people.
Incense was/is used to cover the smell of the corpse until it is put into the grave. After burial there is no smell so what is the point of burning incense?
Traditions handed down by our ancestors are fine for cultural unity, but when they are taken to a level of blind following, ignorant acts, then we violate the clear instructions of Allah:-
2:170 When it is said unto these (satans), "Follow what God has revealed", they say, "Nay! We follow that wherein we found our ancestors.” "What! Even though their ancestors (and the ancient Imams) were lacking in understanding and were not rightly guided?”
[5:104, 10:78, 11:62, 11:87, 21:53, 34:43, 38:7, 43:23. Hudan and derivatives = Prominent = Bright = Lighted = Clearly visible = Leading = Guidance = Lighthouse = A well-lit road = A landmark of identification in the desert or sea]
2:171 The likeness of such blind followers is that (of a herd of sheep) which hear the shepherd’s call, but hear in it nothing more than a sound and a shout. Deaf, dumb, blind, for they use not their reason and, hence, fail to attain good common sense.
[This is subhuman level of existence 7:179. ‘Unq = Shepherd’s call. Shepherd here pertains to religious leaders who have learned some meaningless words or tenets, and a herd of sheep is the masses that blindly follow them. Kufr embraces blind following in addition to denying or concealing the truth. Perceptual senses alone cannot distinguish human beings from the rest of the Animal Kingdom. It is the data processing or intellectual analysis that makes them distinct]