Hard drive - yes
RAM - no
You will need 1.35v Sodimms. Also called PC3L or DDR3L.
can i build in a M.2 SSD and a SATA?
Yes, the system has a M.2 socket for an SSD device. You can have both an M.2 SSD and a HDD/SSHD. Note that the height of the HDD/SSHD is limited to 9.5mm. There are some HDD/SSHD units that exceed this height. They will not fit in the HDD drive bay in the NUC chassis.