Creature types and subtypes in D&D and Pathfinder

While trying to figure out a few hybrid races with the Advanced Race Guide I stumbled into a few issues I'm not sure what to do about.

First of all, if you apply the half-celestial template to an elf "The creature's type changes to outsider (native)." Since he is now not a humanoid (elf) anymore wouldn't he lose all access to elven feats, items, prestige classes, etc?
It gets even more interesting if you do that with a half-elf, because of the Elf Blood entry in their rules. "Half-elves count as both elves and humans for any effect related to race." Would he be considered a native outsider, a human and an elf at the same time? Would he also be considered a humanoid?
There's one alternate racial trait for Aasimar that makes them count as both outsider (native) and humanoid (human), in Races of Faerun there were Fey'ri that had "Elven Blood: For all special abilities and effects, a fey'ri is considered an elf. Fey'ri, for example, can use or create elven weapons and magic items with racially specific elven powers as if they were elves." Would "for all special abilities and effects" also include spells that target humanoids, so it would essentially have the equivalent effect of the new Aasimar trait from the RPG?

First of all, if you apply the half-celestial template to an elf "The creature's type changes to outsider (native)." Since he is now not a humanoid (elf) anymore wouldn't he lose all access to elven feats, items, prestige classes, etc?

By RAW, yes, though the GM may allow the Augmented subtype to also be applied (personally, I would), so it becomes Half-Celestial Elf, Outsider (Native, Augmented Humanoid, Elf)

It gets even more interesting if you do that with a half-elf, because of the Elf Blood entry in their rules. "Half-elves count as both elves and humans for any effect related to race." Would he be considered a native outsider, a human and an elf at the same time? Would he also be considered a humanoid?

Without resorting to including Augmented Humanoid as a subtype, since that is a specific ability of the half-elf, yes, they keep that. A half-elf's type is technically Humanoid (human, elf), so the Augmented trick works, too.

There's one alternate racial trait for Aasimar that makes them count as both outsider (native) and humanoid (human), in Races of Faerun there were Fey'ri that had "Elven Blood: For all special abilities and effects, a fey'ri is considered an elf. Fey'ri, for example, can use or create elven weapons and magic items with racially specific elven powers as if they were elves." Would "for all special abilities and effects" also include spells that target humanoids, so it would essentially have the equivalent effect of the new Aasimar trait from the RPG?

Don't have ARG yet, so can't comment on the Aasimar racial trait, but the Fey'ri essentially have the elf subtype.

Thanks for the reply.

By RAW, yes, though the GM may allow the Augmented subtype to also be applied (personally, I would), so it becomes Half-Celestial Elf, Outsider (Native, Augmented Humanoid, Elf)

I forgot about augmented humanoids, according to the type description it seems as if it was supposed to be used on all creatures with templates, but the Bestiary only used it on the lich.

Don't have ARG yet, so can't comment on the Aasimar racial trait, but the Fey'ri essentially have the elf subtype.

So they would count as elves, but not as humanoids? This is the Aasimar trait.

Scion of Humanity: Some aasimars’ heavenly ancestry
is extremely distant. An aasimar with this racial
trait counts as an outsider (native) and a humanoid
(human) for any effect related to race, including feat
prerequisites and spells that affect humanoids. She can
pass for human without using the Disguise skill. This
racial trait replaces the Celestial language and alters the
native subtype.

I'm not really sure about how it is supposed to work. It seems that it would make the Aasimar subject to all negative effects against both types (even though those have been reduced).

Augmented is supposed to be applied whenever something occurs to change a creature's type. The game rules just don't do it every time they should. Certain Sorcerer bloodlines as well as Perfect Body for the Monk should include the Augmented subtype, but don't.

I mentally add it whenever I should, and it simplifies a lot of things.

That ability certainly does give the best and worst of all worlds. It allows the character to pick human only abilities/feats, and can be affected by the "X Person" spells, human and outsider Bane weapons, and a load of other subtle effects.

I'd only ever take that for concept, not for the "advantages".

I believe this is inaccurate. Subtypes carry attributes that can affect different types, but they do not have any impact on effects related to Type. An elf with the half celestial template becomes an Outsider (native) and should also include Augmented Humanoid, Elf in the sub types but it doesn't make them vulnerable to charm person, as that comes solely from Type.

There's a discussion of exactly this over at RPG.SE, if you want to take a look. (The link goes to my answer directly, you can scroll up to see the question.) http://rpg.stackexchange.com/questions/45283/does-the-augmented-humanoid-su btype-count-the-creature-as-humanoid-for-spell-eff/45284#45284