So I've seen elves referred to as Mer, and all their races end in mer as well. So are all mer elves? or just all elves mer?

Same thing, just elven and human words.

Yes, the suffix -mer denotes that a race is of elven descent. And you could collectively refer the elven races as Mer.

The only exception is the Khajiit, who are likewise mer but do not call themselves such.

Mer is a Merish term meaning "people", as in "Bosmer", meaning "Tree-Sap People", whereas "Elf" is a human term meaning "them pointy-eared fellers".

Mer is what they call themselves. Elves is what Humans call them.

Denoting beings that are not mer, like humans, are therefore not/less than people. Makes sense, given the cultural tensions rampant in Tamriel.

Khajiit are descendants of mer, but Khajiit aren't mer.

The argument could go either way. You can make the argument that if its decended from 'Old Mary' then it's merish, witness the Orcs, or Betmer. Or you can argue that the Khajiit have been changed too radically and who philosophically are not Elvish to be considered one.

... Actually, if they are philosophically too different from other elves, then in the ES world, that makes them different enough to be considered something else, wouldn't it?

If that's the case, then the dunmer, chimer, orsimer (orcs) and bosmer may as well be excluded from the "mer" suffix, since their views are definitely different enough from the altmer, who are the traditional elves. I guess as long as you have long elvish ears, you are a mer of sorts.

But what I'd like to know...how close are the religious views of the orsimer are to the altmer? Yeah they worship Malacath or Trinimac, but what about after that? Do they side with the altmer of trying to go backwards, forwards like men, or neither? If the Trinimac guys want to return Malacath to Trinimac, what do they believe after that? What about the Malacath guys?

Orsimer were Aldmer (Altmer but before all the other Mer left Summerset)who instead of believing in ansectors followed Trinimac. Trinimac was transformed into Malacath, and they transformed with him. They still worship him. They don't car about doing/undoing subcreatons of AE.

I know all about that that. What I am trying to get out is, 'okay, so what next?' Before they became orcs, they were Aldmer that held Trinimac to a higher esteem than Akatosh. But other than that, what do they really believe? Are their views more geared towards merish thought? Is it geared towards mannish thought? Or neither? What about the orcs that'd rather just stick to Malacath?

We know the dunmer adopted a more mannish train of thought and abandoned the merish line of thought. With the bosmer, they did a similar thing, and also 'took mannish wives.' Because of those, to the aldmer/altmer, they're pretty much tainted, and shunned. As noted in the aldmeri beliefs from the Monomyth

The bolded phrase in the second paragraph is what I had in mind. From what little we know of the Khajiit philosophy, they tend towards a neutral interpratation of Lorkhan, leaning towards favor and judging by http://www.imperial-library.info/mwbooks/clanmother.shtml they don't really express a deisre to move backwards, as that would make them Bosmer again. So, philosophically not elvish at all.

As for the Orcs, judging by Gortwog's desire to uncreate Malacath back to Trinimac (don't think about that too hard), I'd say that they definitely do want to move backwards. If only for such short-term goals like no longer being pariah-folk.

Gortwog's heresy was his belief the digestion never happened, that Trinimac and Mauloch were not the same person.

But that the mantle was forced onto Trinimac. Mauloch was some demon "holding Trinimac prisoner" which is just a different way of saying forced mantle ala Sheogorath's claim of Jyggalag. Free Trinimac and you have to get rid of the Pariah-God.

I havn't found anything to suggest that is Gortwog's belief, that Trinimac is imprisoned in the person of Mauloch. Gortwog honestly believes that Trinimac is all together another. He wouldn't be a heretic if he believed them the same person, nor would Malacath's Orcs care.

Not necessarily, because the elves use it to refer to other races as well (i.e., nemer for "not folk", non-elves, and "betmer" for "beast folk"). Kinda like "lizardman" (to use an old Arena monster, even though they've probably been since retconned out of existence) are not human despite the "-man" suffix.