#1 - 120yds of 10lb test mono ... correct !
#2 - yes/yes/yes
#3 - yes ... but, less than how you have your brakes set, how good your casting routine is, and the weight & shape of your lure.
Yes, braid is more expensive than mono .... but, in terms of $$ per amount of time the lines are still suitable to fish with, braids are actually cheaper in the long run (since they last many times longer than mono). A 150yd spool of braid should be enough for 3 reels ... depending on how you'll be fishing with them. Use some old mono as backing - lighten up your drag - have a wood dowel rod handy, to wrap braid around, for pulling lures free from snags - have a pair of Fiskar Childs Scissors for cutting the braid in a nice clean/blunt tag end, as that makes for easier lure attachment.
.. cp