Oh please, the mentions of having to seek alternative funding models like subscriptions and ads are clearly meant to raise the image of a site on the brink of unsustainability to potential donors
The implied subscription threat is a complete red herring. They should be ashamed for even mentioning it in their fundraising messages.
Wikipedians wouldn't work for free for a subscription service. The whole project would fork to a new host. The Wikimedia Foundation's own mission statement says, "The Foundation will make and keep useful information from its projects available on the internet free of charge, in perpetuity."
You can't contribute donations to Firefox; you can only contribute to the Mozilla Foundation, which spends most of the money it gets from donations on things that aren't Firefox.
Sure. And if you accept those images or not is your thing. Their banners are super annoying at only 2% conversion rate. What will it be without those banners?