Well the crew spend a lot of their time in hypersleep, which the engineer dude says in yet more heavy-handed exposition to the junior engineer. And you don't age in hypersleep. Hence the very high pay. But they're shown as waking each other in shifts which implies that there are always some of them awake at the same time.
Given how Yutani for whatever reason is willing to let a fairly top of the line looking star freighter like the Maginot would be in the mid 2050s to go on long expeditions like that, I'm not surprised that they'd be forced to get out of shifts. Hypersleep is a process that has some negative consequences if stuck in it for too long, somewhere between a couple of years to a decade after entering the freezer. I believe there also is a small chance of a malfunction that is lethal too, so having someone check isn't a stupid idea.
The problem is what resupply would they have, and how do they stop information leaks; they'd need to actually have proprietary infrastructure all throughout their search for CGI shitslop monsters. Also the amount of money wasted on this endeavor over just having shorter probes as you chart space do it for you. Again, the Nostromo doing it makes sense; it was a company asset enroute and passing through. The Sulaco in Aliens likely was the nearest vessel for an expedition and had its team selected due to a combination of the NCO's logistical and leadership ability and willingness to listen to command, and Gorman's inexperience allowing Burke more leverage.
You need to have a logic in the Maginot. I'd have personally made it a scout ship set to stake planet claims and for asset acquisition. With that in mind you'd need a pretty good crew, likely a team ironically closer to what the Prometheus was supposed to be. Geologist, Astronavigation/Physicist to chart systems, Xenobiologist, Corporate Warrant Officer, Medic, that sort of thing. Shame they're played dumbly.
TBH that's a factor in why I don't buy the Maginot being out there for decades like that, especially since besides Prodigy they seem to be doing shit all with the other companies. I can't wait for them to fuck up Seegson. Why not ask me about our amazing writing staff.
And the fact that they are not freezing the creatures means that yes, there are expectations that you can keep all of them alive over decades of journey as you later point out.
That's pretty damn stupid too, since for all you could argue that freezing them might not affect them or kill them, they'd still be expected to need resources to survive. Well I guess the Xeno doesn't, since a big factor on it having acid for blood is it ambiently gains energy from ambient atmosphere. If I had to guess its blood is akin to a chemical battery and it just needs access to some energy to store in it.
But that'd still be something you'd need to factor in; food and containment.
It's an interesting idea who you might pick for a sixty-year voyage. You have two routes as I see it: You pick people who due to trauma or personality issues, have no close connections to anybody and might be willing to just sign up for a misfit crew off on a mission with a promise of returning rich one day. You can even market it to them as an in-built social group of new friends with a shared purpose. Or alternately you can take existing close relationships and transplant them wholesale, typically couples who want to spend their time together. I don't need to highlight how risky the second one is of course.
For all I shit on and dislike Covenant, I can at least state that Ridley Scott was smart enough to actually think of this when he set and made it a colony ship. All crew were couples or in relationships or closely bonded. Allegedly. This was also the logic that James Cameron had for Hadley's Hope; the terraforming and wildcatter crews would perform more if they could cart families to the ass end of a shit rock like Acheron.
Also, FWIW, in the lore hypersleep isn't just about passing long months without consuming supplies or uselessly aging doing nothing. It's a necessity because going faster than light fucks with your mental state. Though that's never been depicted in movies.
It's mostly hinted in other media and most pushed by the RPG, but essentially a strong form of space cabin fever occurs due to staring and functioning in a state of space-time that humans aren't adapted to it. They don't explain the why, but eventually it results in severe mood swings and psychosis, as well as some mental acuity decline.
Also fun fact; to ensure you don't go mad in the tube or suffer brain damage, it's extremely common for pods to allow just enough neural activity to dream. It's a big factor in Ripley being fucked up in Aliens; she had nightmares about the Nostromo and the Xeno for all those years.
Other fun fact: dreaming is a legit business and commodity in Alien's setting. Good lucid dreamers are their own niche of entertainer, and their dreams often get sold specifically to aid hypersleepers.
That was the intent, according to Hawley on the official podcast:
Well he botched it, just like he did his awful retelling of Alien to pad run time due to not having anywhere near as good a story for a TV show as he thought he did. It makes the eye-thing look more like a 'hero monster' due to that failure in execution. Compare to the old idea that Kane's Son and Jones were working together to kill each other due to how the cat stared and slow blinked at Brett's death.