Quick thoughts on Halloween and a possible link Samhain/Divali

The name "Halloween" is the contraction of "All Hallow's Eve", a Christian name for a festival that is not that Christian...

I. Samhain or Samonios: Halloween's ancestor

The celebration of the Christian Saints (All Saints Day) was officially placed on November 1st by the Pope in 835... Before that, it had been held for over a century in early May, and scholars think the Christian festival was modeled on the Roman Lemuria festival, a kind of festival of the dead. In England, it seems the All Saints Day was already celebrated on November 1st in the early 8th century, and the official decision to move the feast simply followed folk customs. [1]

The end of October/beginning of November (the date was moveable according to the lunar phases) represented for the Celtic people of Antiquity the end of the year et, of course, the beginning of the new one. Known as Samonios in Gaul, Samhain (or other variations according to the region) in the British Isles and across the world today among neo-pagans, many of these festival themes survived and evolved in our modern Halloween.

The end of the year indicated for the Celts the entry in the dark season, where the nights are long, the weather cold, the soil barren. On Samhain, ancient people bid farewell to the sunlight. Summer was truly over and the last harvests were completed. Entering a period of seasonal and natural darkness gave birth to a folklore of closeness with the underworld, the world of the dead.
Among the Gauls, the 3 days that lasted Samonios were apparently considered as outside the rest of the year. Their standing alone emphasizes the idea of threshold: between the 3 celtic seasons (light and dark) and between 2 worlds (the living and the dead). Neo-pagans today still hold the idea that on Samhain the veil with the spirit world is at its thinnest, and that the period is ideal for divination.

II. Links with Divali 

Divali is Indian festival, often called "Festival of Lights", celebrated during 5 days around the end of October/beginning of November, and a wide tradition makes of Divali the New Year celebration.

I'm wondering if there could be a PIE (proto-indo-european) origin to both Samhain and Divali. I haven't looked into Slavic, Germanic and other IE traditions yet, but I've noticed some common points/themes between the Celtic and Indian festivals. Taken individually they don't mean much but put together a link can be seen.

1. The period when the festivals are celebrated.
Both festivals occurs around the same time of the year, both are moveable and take into consideration the lunar phases.
2. The festivals announce the new year.
This is espacially true among the Gujaratis, who are of Indo-European descent. [2]
3. The importance of light during the festivals. 
"Divali" is the contraction of "Deepavali", meaning "rows of lamps". During the festival many small clay lamps (called "diyas") are lighted. This tradition has several meanings. One is that the light ward off the evil spirits. Another is that the lamps remind of and honor Yama, the God of Death, who in a legend was kept from taking the life of a man one night by all the lamps the the man's wife had put and lighted in their bedroom. [3]
On Samhain, bonfires were lit, this ritual probably illustrating the continuity of light despite its weakness to come. The spirit world was also the closest during that night, and ancient traditions included leaving some food for wandering spirits and ancestors. [4]  Of course, there is also the legend of Jack O'Lantern [5], still present today when we carve pumpkins and put candles in them.

These common points could of course be just coincidences, since the themes of light and the underworld are widely found in mythologies all around the world. However we do know that all the modern Indo-European cultures are linked through linguistics as well as spirituality and folklore. I plan on finding information on other IE traditions (Slavic, Baltic...) that could be linked to Samhain and/or Divali, to determine if there really is and IE root behind the 2 festivals. If anyone has information to share or books to recommend, don't hesitate! :)

[1] http://en.wikipedia.org/wiki/Samhain#All_Saints.27_Day
[2] http://en.wikipedia.org/wiki/Gujarati_people
[3] http://en.wikipedia.org/wiki/Dhanteras
[4] See research by Jack Santino, scholar specialized in folklore: http://www.loc.gov/folklife/halloween.html
[5] http://en.wikipedia.org/wiki/Stingy_Jack