Firstly a big welcome to the forum, thanks for signing up and I do hope you stay around and add to all the discussions on here. I started up this powerlifting section of the forum a few months back, it's still relatively new but there's already a good amount of info (and motivation) in there. Speaking from my own experience, I'll answer your comments in red as best as I can.
1) In consuming plant-based proteins, how do vegans typically measure their intake to ensure they are complete? Do people typically mix equal parts incomplete proteins, or favour those food sources richer in BCAAs?I personally don't measure anything I eat, I don't know how much protein I eat or carbs but I don't think I have ever had a problem gaining muscle and strength (bodyweight yes, but I know that's because I never really consistently eaten a large enough daily caloric in take). I pretty much just eat when I am hungry ensuring that I eat regularly throughout the day; what I eat and the portion sizes depend on what I need to be doing with my weight. Funnily enough the first time I competed in a powerlifting meet I was 150lb, then I dropped down to the 130-145lb class and now I am planning on dropping down to the 117-130 class when I next compete. So far I have managed to continue to increase my strength, being considerably stronger weighing 139 than I was at 150. In terms of BCAA's I use a pea protein that contains 9 essential and 9 non-essential BCAA's, everything else I just get through food.
2) Has anyone gone through a significant bulking phase (moved up a weight class or two)? What food sources do you use to consume 4000+ calories per day while ensuring 2g/kg BW? I've found some vegan diets online of a 'eat this to gain muscle' sort. However, these do not give the way, nor list the number of calories relative to activity.My competition bodyweight compared to what I am when I'm training isn't too far apart, when I want to add weight I'll just increase my healthy fat intake such as coconut oil, avocados, raw nuts and take more of my omega 3 oils (I use one that sources EPA/DHA from microalgae). I eat similar foods but probably add in more snacks through the day and increase the portion sizes a little. I'm interested to hear what people are eating to consistently be hitting 4,000cals a day though
Good luck with your training, look forward to seeing you posting more around the forum. Have you competed before or are you looking at getting into it for the first time? Kind regards and all the best with everything MF.