Ubuntu OS on eMMc with uSD Card Tie-In

The following is my goal in setting up my BBB rev.C. After much time spent in searches and forum, I found much scattered information,
but could not seem to put it all together.

  1. If possible, flash the 4GB eMMc with Ubuntu 14.04 LTS, including the desktop.
  2. Utilize my 16GB uSD card on the BBB so that it will work as an extension to the eMMc. I will want to use the card to mount many

To accomplish Items (1) and (2) I have the following questions and observations:
A- Is the 14.04 distro a good match with the BBB. Some people seem to favor 12.04 or 13.04.
B- Is the Unity desktop a good match. Some people seem to favor LXDE.
C- Does the 4GB eMMc have enough capacity to hold both the OS and the desktop. If not, can I put the desktop onto the uSD card to
work with the OS, along with other applications.

I know how to flash the eMMc with an OS, such as Ubuntu. However, that’s as far as my experience goes. Being a Newbie I do
require detaled answers to Items (A. B & C), and step-by-step instructions on how to accomplish this goal.

Let me thank you in advance for your responses.