There are a bunch of ways to build a long-lasting, well performing shower. If you use something like Kerdi, you need to use their drain. A conventional showerpan needs a waterproof liner and a setting bed of mortar on top of the preslope. If you plan long, hot, steamy showers, you might want to consider building it to steam shower specifications and a surface membrane will help prevent that high vapor pressure from penetrating and making things take much longer to dry out, although the relative humidity in Anaheim is fairly low, if I remember, most of the year. ALL showers require a vapor barrier either topically applied, or behind the cbu on the walls (not both!).
There are so many little details, it's hard to cover all of them in a situation like this on a forum. MIss one or more, and the 'system' may not perform well.