What XBee / USB items do I need for HA-enabled Zigbee on Raspberry Pi?

I want to set up a Raspberry Pi B2, running Jessie, with Zigbee that can connect to a home automation hub (Samsung SmartThings). I’ve been told that I need an XBee S2C to do this, along with some kind of USB adapter for the S2C (I want to use the USB port for communications, rather than wiring to the Pi’s digio pins for serial.)
Can anyone list for me exactly which items (with exact part numbers) I need to do this? I ask for exact part numbers because there is a bewildering array of XBee options.
First, of course, I need an XBee S2C itself. I don’t think I need the Pro, but I want through-hole for working with the Pi, no? So maybe the XB24CZ7PITB003 with a PCB-mounted antenna? Or do I need a wire antenna (XB24CZ7WITB003)?
Then I need an adapter board. Digi helpfully pointed me to SparkFun; I’m wondering if the WRL-11812 Explorer USB or WRL-11697 Explorer dongle will work? (The first would require a USB cable, I do understand; I might choose it because the mounting of my Pi might not allow enough room for the dongle.)
Anything else I need? Or don’t know?

XB24CZ7PITB003 is a Programmable module. It does the same thing as having the Pi and a xbee module just without needing the Pi.

Instead you would want the XB24CZ7PIT-003.

I too eagerly waiting to know the detailed view of this. Please explain me in-depth.

Haritha, who are you asking?

Haritha,

The Programmable XBee modules have two processors on them. The first is the RF processor which houses the firmware provided or accessed via XCTU and allows the network to form.

The 2nd is a freescale 8 bit processor that is located between the radios Pins and the RF processor. It is designed so that you can write an application and port it to this processor. It is intended to take the place of an external 8 bit processor so you have one less item in a parts list for a finished product.