Should I move my home folder to my HDD to reduce writing to the SSD?
To disable hibernation go to terminal and type 

sudo pmset -a hibernatemode 0


If you'd like to reenable later down the line use:

sudo pmset -a hibernatemode 3


As far as moving the home folder, I feel is a bit silly given the price of ssds. If you do want to do it that's fine, but I don't think most people would suggest doing so. Especially given that it's an external drive connected with a cable I would suggest leaving everything on one drive. Less chance of things going wrong, just make sure you have back ups.