Is a b guitar essential in a band,and other questions?

For live sound, the b wont be AS important, but you notice it missing when its not there. For recording purposes, absolutely have b. Depending on your idea of not expensive, schecter makes great guitars for what you're looking for, I personally dont like Ibanez but they aren't bad guitars, BC Rich guitars (in my opinion) are really more for looks than playability unless you get a high end model, their high end guitars are great. Epiphones also aren't bad, but its worth it to save the extra $200 or so and get a high end schecter. As for making it big, nobody can really say. You have to understand that you're not exactly playing the most marketable genre (not hating on deathcore, its just not as popular as other ****). All you can do is make sure you guys are REALLY tight before playing a gig, get GOOD recordings asap. Dont put shitty recordings up, becuase you wont be taken seriously. Its a huge financial commitment to be in a serious band, so just be prepared to work your es off, put money into it, and dont expect to get it back for a long time. My band did a tour of the NE United States and after gas, hotels, and other expenses, lost about $400 per member. But we had a blast and got our names out there. Lastly, play shows out of your own town. Dont be stuck forever in your city, branch out. Hope this helps, and good luck!