Hi there,
For the Fast Boot, you need to make sure that Hibernation is enabled. Fast Boot only works when you shut down the computer, not when you restart it. Truly, you didn't have to change anything in BIOS in order to install from USB. When you place the empty SSD in the bay (nothing on the other bay), and the USB stick, BIOS is smart enough to recognize that you are doing an install (just did it Saturday for my new SSD).
Intel Rapid Storage is important in order to optimize the HDD/SSD.
BTW, what BIOS version have you got? Though people are scared to update BIOS, it is usually a good idea. Make sure you DON'T turn computer off or cause it to lose power while updating BIOS (takes less than a minute usually) as you will turn your laptop into paperweight.