You need to do some basic research about nutrition. Read the stickies in the beginners forum and many of the hundreds of other great nutrition articles on this site. Then simply do your best to find protein substitutes. Rice and pea protein are pretty good... better than soy. I'm guessing milk based proteins are out too right?
Anyway, you can lose serious weight in 8 months if you stick to it. You have to attack it hard core and get your diet right. Developing good health habits is going to be key to long term results, so whatever you do make it something you like. Foods you can see yourself eating and exercises you can tolerate. If you have issues with lifting weight (some people do) you have to get over those because you must lift weights to have good results! The research on fat loss and resistance training is clear on this. You don't need to make anything complicated, just eat healthy food, but always stay a little bit hungry. That's my rule of thumb. As for exercise try and get in 2 shorter weights sessions per day if possible and throw in some HIIT where you can.
As for vegan nutrition, you'll also want to get a source of vit B-12 as vegans often have insufficiencies of this vitamin.