I'll respond to the specifics later on, but for now, suffice it to say some people just can't add muscle without meat. It's certainly true, and please don't ask for references.
Do you have a reference for that?
Also, you must eat a LOT if you're veggie because of the small quantity of proteins, carbs, fibers in veggie items. These are the obvious disadvantages.
I would suggest you go to some nutritional database and check out the nutritional value of things like soybeans, chickpeas, lentils, tofu, seitan, pasta, rice and then rethink your position on this issue.
Out of curiosity, why are you guys vegans? Is it from a health perspective, or on account of ethical considerations, like you dont wanna hurt animals? For me, it's the latter.
If you are against killing animal, why do you think it's ok to eat meat every now and then?
I am a serious vegan bodybuilder.
Out of curiosity, are vegans permitted to drink milk? if not, why not?
No offense, but how can you be a serious vegan bodybuilder when you dont know what a vegan is? Perhaps this link
may be useful