1. You can eat them if they have the nutrients you need. Non-carbon-based just means it won’t use carbon as the foundation of its molecular and cellular workings. By mass, there’s relatively little carbon in living organisms and on earth, so whatever’s out there could still use carbon and other elements enough that it has something we could eat. There’s barely any telling what kinds of chemicals will be found in an organism like that, but it could easily be a mix of things we can digest and things we can’t. Even carbon-based life is like that. Wood for example is biologically very similar to us, but is mainly made of cellulose, which we can’t really digest at all.

2. yes, if it fits.

We can probably do it once, but we might have to choose one or the other.

Both of these are matters of will.

God I hope it’s slime girls

Both of those questions will depend on what kind of environment they need to survive. They might need pressures higher than we can or a pH that would be corrosive to us, or exposure to an chemical that is toxic to us like oxygen was to most life that was around when photosynthesis started producing it.

If we can make physical contact with it, we’ll be able to eat it. But if it is based on a different chemistry, I doubt there will be much nutritional value for us as our proteins and vitamins are all based on our chemistry. Hell, there’s a good chance we won’t get much nutrition from alien life based on the same chemistry because they might have evolved with a completely different set of proteins that might do things similarly but connect with each other a bit differently. There’s a symmetrical set of proteins that look like mirror images of ours and would behave exactly the same, but aren’t compatible with ours.

1st question: no.

2nd question… Depends how horny and desperate you are.

Is there anything we can’t fuck?