Insulation & moisture barrier needed in SoCal?

Hello, newbie here. This is my 1st post.
I live in Southern California & my house is about 45 yrs old. I'm installing a "Sterling Vikrell" shower enclosure w/ receptacle. When I tore out the existing shower there wasn't any insulation or moisture barrier, even though two of the shower walls are outside walls. The old shower had mud walls w/ showerboard.
The Vikrell shower is supposed to attach directly to the studs, but I have several questions, so here go's.

1. Should I install fiberglass insulation w/ a moisture barrier behind the Vikrell shower walls?

2. If so, should the paper on the insulation face the inside (towards the shower) or outside (towards the stucco) of the wall?

3. Do I need to insulate all the way up to the ceiling, or can I just insulate to the heighth of the shower wall? (Right now the opening in the drywall only goes to 4" above the heighth of the shower wall. I don't really want to tear off anymore drywall than neccessary).

4. What is the best moisture barrier to use?

5. If I don't install any insulation, should I still use a moisture barrier?

6. The inside shower wall has an electrical outlet & light switch in it for the power room on the opposite side. What condsideration should be made regarding them?

Sorry soooo many questions. I want to do it right, so I don't have any problems later.

Thanks in advance for any advice.
Jheels

WIthout insulation, you are conditioning the outside, your call since you may not need much during the year. Vapor barrier probably won't make much difference if the cavity is not sealed. In warm climates where they primarily air condition, they often put the vapor barrier towards the outside; in areas where they primarily heat, they put it on the inside. You are trying to keep the moisture from condensing on the cooler side. The shower wall is waterproof, I'd just install some in the wall to keep it a little mroe comfortable. You could stuff some up wall cavity above the shower walls. The kraft faced stuff is easier to install...you could slash the paper a little so you don't cause a "moisture sandwich".

Don't worry about the wires in the wall...won't cause any problems.