well i can answer two of those questions for ya,
a vexilar is like a fish finder, here is a pic to show you how it works, you can see you jig go down on the screen, and you just let it fall to the fish, then jig em up, you can then see a line start moving up to your jig, representing a fish, you can see where i circled the bottom on the top of the screen, and the fish toward the middle
the vex has helped me and a buddy ice 860 fish so far this year, now that i've used it i wouldnt go fishin without it!!! and others will tell you the same!! You wont be sorry you bought it if you did!
Yes maggets will work but i prefer spikes at least in michigan, red spikes, glow spikes, pink spikes, and just the regular old spike, and also mousies. Hope this helped good luck fishiN!