Hydroponics? Starter pack of bacteria to condition the soil on the new world? Maybe there's already soil there that would be suitable with some prep work? We can't actually get a close enough look to say whether any given exoplanet is a lifeless rock or not. Any such colony ship would surely be preceded by a survey probe, so the robots would draw water from the environment.

And yes, I know they don't send literal cans of soup into orbit. I'm sure you can forgive a convenient turn of phrase even if it wouldn't be part of a technical specification for NASA.

Slow communication is still interaction. If I write a letter and send it to my mother via snail mail, does her response not count as 'interacting'? That seems like a silly way to twist the meaning of the word. That being said, communication with a 20-ish-year latency (now thinking of places like Wolf 359 or Ross 128) would be a different model than what we have now.

Actually, that raises another practical issue. How do you send a coherent signal over such great distances? Directional radio antenna? Laser comms? The power levels and precision needed to make a direct transmission work might not be feasible. OTOH, you could launch relay probes at regular intervals to simplify the problem, so it wouldn't be insurmountable.

There's definitely the risk that an "early" colony vessel would be completely obsolete by time it arrived. I read a story a while back where humanity sent a diplomatic mission to an alien homeworld via a coldsleep ship. While they were having tea with the alien emperor, Earth's first FTL ship arrived! Definitely the kind of stuff that would make some aerospace engineers despair.