Well this is my first post on this forum so first off; hello.
So a vegetarian… prepare to be picked to pieces. Although not by myself.
Let me tell you that as a vegetarian myself I find that you definetly still can gain mass contrary to popular belief. I have personally gained at least 40 pounds in the last 2 years which one of those years being a vegan and not training consistently. I was very light lean and not very big; about 155lbs at my lowest. This was due to involuntary starvation (completly unrelated to veganism by the way… I know what your all thinking). Anyways got back to eating and going to the gym and am now shy off 200 lbs.
Many athletes even body builders are vegatarians (Bill Pearl comes to mind)so it can be done and has been done.
As for protein the sources you indicated are good. I am all about the legumes personally and nuts are awesome too. Tofu is good but stay away from other processed expensive soy garbage. They are expensive, not easily digested, extremely processed and contain phyto-estrogen. It’s just a industry like any other trying to make a buck by making you think it’s such a great source of this and that. Forget it, it’s not worth it.
As for carbs, if they come from beans or even whole-grain or rice, don’t worry about it. It’s the white ultra-processed junk with sugar as a main ingredient and about 23 other random ingredients you can’t decifer that you should worry about.
Hope this helps