Hi Anthony
Do the Kinetis devices come with a set of libraries enabling I2C, SPI functionality out of the box?
There are examples on the DVD (Included in the package when you buy a board) and the Freescale Official Page on how to use those protocols.
Is there a development board that incorporates an on-board LCD?
I'll attach a PDF showing our products.
You can also buy a TWR where you can get a TWR-LCD and just attach it to the tower.
Are there any plans to supply Ethernet libraries and development board with Ethernet capability?
TWR boards have an TWR-SER to implement Ethernet.
I recommend you getting a TWR-K60N512, it's very flexible and it comes with a modular Tower System development platform. where you can adapt Ethernet, Serial and USB with the included TWR-SER.
I'll leave you the link: TWR-K60N512 Product Summary Page
If you have more questions I'll be glad to answer.
Hector Sanchez