I've been trying to aquire some knowledge of their religious culture. I've been browsing various sources, and it appears they have ten gods, even though Lorkhan is considered an enemy (I read through the history of the Dawn & Merethic Eras).

It's mentioned Auri-El is the Altmers' Akatosh. I've been curious if this means Auri-El is just another name for Akatosh, but they are the same individual, or if Auri-El is the equivalent of man's Akatosh in the sense they are each the chief deity of their respective race, but are completely separate entities. (I read that Auri-El is the soul of Anui-El, who in turn is the soul of Anu)

I also noticed Mara and Stendarr were listed among the ten Altmer gods. Does this mean the Altmer have shared gods with man?

Is there a symbol that represents Auri-El, like what you may find on an amulet of Mara?

Holy texts, rituals, symbols, etc. As much information, and clarity, on the subject as possible would be greatly appreciated.

All the races' myths are very interconnected and are basically a telling of the same ancient mythic events that shaped the Aurbis, but from different cultural biases and perspectives. For a chart on aspect equivalencies between pantheons, http://www.uesp.net/wiki/Lore:Gods. Even esoteric religions like the Skaal's are echoes. The All-Maker is probably An Akatosh aspect, and the Greedy Man is probably Lorkhan.

The http://www.uesp.net/wiki/Lore:The_Monomyth, http://www.uesp.net/wiki/Lore:Varieties_of_Faith..., and the http://www.uesp.net/wiki/Lore:The_Old_Ways are good places to start. Do note though that the Old Ways predate the modern veneration (or corruption) of the "better" ancestral spirits, A.K.A the Aedra as we know them.

What's also worth noting is that the while the Altmer worship a similar pantheon to mankind (Well, all races save the Dunmer and Argonians do, at any rate), they have radically different ideas of them. Stendarr for example is the "Apologist of Man", which is probably the closest thing to mercy the Altmer would bestow on the lesser races, and we don't really know how the Altmer interpret Mara or Kynerath under the Altmeri pantheon. Auriel is the Altmeri take on the Time-God, as the Alessian versions is Akatosh. Said interpretation is more based on a glorification of the past, and a return to the good ol' days before Mundus was created, whereas Aka worship is more geared towards the present, ever lasting legitimacy, so on and so forth. They're functionally the same deity in that they both govern Time, but that's where everything gets complicated. Suffice to say, yes, they're the same, except at the same time radically different.

As for symbols...the Sunbursts in Dawnguard that the Falmer used are our closest indicator, as the Falmeri pantheon seems to mirror that of the Altmer to some extent. How different and what aspects of Auriel they play up is something we don't know.