Yes. That will work fine. I have 4'' of copper on my NF and with three bands it gets ~70' ranges. Also, your darts should fit pretty tight. At least tight enough to where you have to you some sort of stick to get them in the barrel (I use my pinky).
Hmm...Well...Not necessairly semi-automatic. You can just get off more than one shot before you need to pump it up again. So..it's pump,fire,fire,fire,fire,fire. Understand?