Death Rites

Sol'Aeldvari
Cremation of the dead is almost universal across all sun elf cultures and settlements. Capturing some of the dead's ashes into small blown-glass trinkets or jewelry is common for immediate family (especially spouses and adult children). Most homes include carven thresholds that recount the lineages of those who lived and died within that family.
Ancestors are often addressed as immaterial spirits within the sky, wind, or smoke. Lit flame is not home to the ancestors but can be offered to "feed" them or honor them. Living sun elves regard the ancestors as a sort of diverse but vague group, "smoke in memory of the flame," with the exception of those personally loved and lost in close families and friends.
Lun'Aeldvari
Many moon elf cultures practice "living" burials or green burials, interring the bodies of the dead into the earth and cultivating trees or other plants to grow over and from them. Some places have gardens of the dead, where herbs, flowers, or even tea and fruits are grown and shared with the community. Others tend groves where a sapling is planted over each dead body. Some communities have enormous old trees whose root systems are so dense and knotted that the dead can be carefully deposited into natural "tombs" in the nooks of the roots.
Most moon elf communities have a dense list of rituals, prayers, and festivals that acknowledge, honor, communicate with, and remember the dead. Their ancestors are regarded as individuals for as long as the memory of that individual lasts, and ancient social conflicts may still be acknowledged within the rites that call upon the dead's wisdom and blessings.
Among the dozens of localized traditions is a particular type of prayer. If a tree grows from the deceased, one can (carefully) harvest a small number of branches, pulp them into paper, and write letters to the dead. Those letters are usually sealed and either buried near the tree or burnt in offering to the tree.
Gran'Duovari
Stone dwarves live their lives and bury their dead almost entirely underground, often deeply so. The dead are given to the care of specific families dedicated to their service, and the bodies are offered to the mushroom gardens or insect farms that provide most of the food to the community. Once cleaned of flesh, their bones are collected and usually deposited in a large, meticulously-carven urn, though if space, time, or wealth is scarce, the bones may be powdered and poured into a much smaller urn. The urns are stored in carefully-organized catacombs, open to the entire community for visits and small gifts (usually tiny trinkets, gems, precious metals, or shot glasses of alcohol).
Everything that the dead possesses passes to their immediate family, so no wing of the catacomb is larger or fancier than any other. Each urn is equal, though the inscriptions upon it are unique and may still sneak in some differences - like inlaid metals or stones, fancier-than-usual script, or delicate illustrations around the epitaph.
Ancestors are usually addressed matter-of-factly and spoken of as though absent but still-living family members. Some dwarves refer to the ancestors as "living in the stone now," "beating the mountain drum," or "at Mother's hearth." Most dwarves include their recent and closer ancestors in their daily meals, conversations, and day-to-day life, but don't treat them as supernaturally powerful - they talk to the memory of their loved one, but don't pray to them for guidance or help.
Dar'Aeldvari
Deep elves vary drastically in how they celebrate their dead. One common method is to sever and preserve the head, which may then be placed in a sacred or idolized place--or mummified and attached to someone's belt for everyday company. Many deep elf communities dispose of dead bodies in a similar way as gran'Duovari, using the flesh to fuel their food sources and then retrieving the bones, but it's as likely for a deep elf family to carve prayers and poetry into the cleaned bones as it is for them to make gaming dice out of knuckle bones. Whether a deep elf community treats its dead as holy, untouchable, godlike, or as natural, casual, and pragmatic is unpredictable from the outside, and different families will often cross between seemingly-callous disregard of the dead's body and ritualized sacredity with no warning.
Most consistently, deep elves treat their ancestors as the very same people they were before they died. They will share the day's news, gossip, melodrama, and smalltalk with their ancestors - usually through a physical token (such as bone strung on a necklace) or by talking directly to their ancestor's mummified head on the mantle. Deep elves constantly communicate with their ancestors, close and far, in waking and especially in dream. Their "prophetic" meditations and rituals are usually performed with the proclaimedly-direct assistance and involvement of their ancestors; debates, conversations, and outright arguments are had aloud between the living and the invisible, silent dead.
It is difficult for non-dar'Aeldvari to ascertain how sincere deep elves are in their frequent engagements with their dead. Dar'Aeldvari are not in the habit of answering such obtuse questions.