@fresco,
What do you mean by 'medium' in your first sentence?
For 3, I believe most scientists know better than that. Let's take a certain biologist as an example: when Maturana states that "life is an autopoietic system", he is not
really making an ontological statement, IMO. He is just saying that living organisms
behave a certain way: they self-replicate and repair themselves.
Likewise when another biologist (me) says: "life is information bossing matter around", he is not really saying anything about the essence of life, just that living organisms maintain their structure by organizing a complex 'flux' of matter: eating, digesting, replacing broken components by new ones, and excreting the waste.
It's only when they need to explain these things to lay people (or to themselves when they are lazy) that scientists use ontological statements using the verb "is". Replace "is" by "behaves like", to get a better sense of the real epistemology at work.
At least, that's the case for scientists who adhere to the Kant-Popper-Kuhn epistemology, whom i would think form a large majority by now.