layer styles - temp turning off

I don't believe there is a default keyboard shortcut for hiding Layer Style Effects, although one could assign a keyboard shortcut to Layer>Layer Style>Hide All Effects

That doesn't actually turn off the layer effects, if that's what your looking to do, it only hides the effects list in the layers panel

Alt/Opt + click FX toggle arrows shows or hides all layer effects

* Brightness/contrast slider for textures when painting ?

Is for the Brush panel>Texture

(Window>Brush)

* Enabled Split Channels for documents with single layer (so you can split simple transparency) ?

In older versions of photoshop when one wanted to split channels, the document needed to be flattened and thus any transparency was lost.

(Window>Channels and Split Channels from the channels panel flyout menu)

In photoshop cs6/cc you can split channels on a layer with transparency and one of the resulting documents will be the transparency channel

(you still need to have only one layer in the document, but it doesn't have to be flattened)

* Can rotate 90 degrees with even x odd pixel dimension to avoid landing  on a half-pixel position. (To enable this behavior, Snap Vector Tools  And Transforms To Pixel Grid must be selected in the General  preferences.) ?

Means when you have Snap Vector Tools  And Transforms To Pixel Grid checked in the General preferences, rotating an object 90 degrees doesn't produce anti-alised edges as it sometimes did in previous versions of

photoshop, still some depending on the object, but not as much as before.

Ctrl+Alt+Z should go back more than one history state

(that's the photoshop default unless one changes the shortcut in Edit>Keyboard Shortcuts>Application Menus>Edit)

What happens when you try?

In the the Brush panel and click on the word Texture

You can only have one layer in the document

Ctrl+Alt+Z should work the same as in previous versions of photoshop.

Did you check the shortcuts to verify Ctrl+Alt+Z is assigned to Step Backward?

Are you using a custom keyboard shortcut file?

If you reset the keyboard shortcuts to the Photoshop Defaults, does that make any difference?

When you Alt click on the FX arrow it just closes the list(s) for the layer effects and that doesn't work?

What operating system and version of photoshop are you using?

Maybe you need to reset the Photoshop Preferences file.

http://forums.adobe.com/thread/375776?tstart=0