>>103554051 (OP)
>Is there somewhere in the Cover quarterly report that you can extrapolate from?
You don't need those reports because most data can be accessed for free, and you can use it to estimate the bare minimum each member is making.
FYI, Coco/Kson have mentioned Cover takes 50% from merch sales, and Pekora/Marine talked about the default 50-50% split for superchats (after YT's cut), and it's most likely the same cut for members. For sponsored game streams it seems that vtubers/streamers are paid 10-30k for a ~10k CCV stream, and that was corroborated not only by recent sponsors complaining about Twitch bots, but also "ancient" chink leaks that showed NijiEN organs like Vox for B2 shill streams made around 10k USD.
As for how much merch each talent sells, you can (or could) actually see decreasing available items inventory on the official holoshop and thus get the number of available items for sale/preorder. It's also possible to use bots to query Shopify platform to achieve similar results. On top of that, a lot of EN talents were making sales on Geekjack.
Gura's "shittier" official merch runs used to hit $500k, and her dino plushie broke the record of sales (according to Gura) while other members like Pekora were hitting 1M for every major merch sale like Birthday merch. I vaguely remember that while Vesper was still there, he'd sold 50-70k worth of merch on the official shop and probably at least half that on Geekjack, and he was a shitter by Hololive standards. At the same time HoloEN members had ~200-270k sales (except for Kronii) for their equivalent merch runs JUST on the official shop.
Tl;dr
EN and JP holos all have at least 1M USD after doing it for 2-3 years, and top ones have millions. This is especially true for talents who don't really "invest" back like Gura.