Curious about this too, and went looking at the interests of my colonists in my newish colony. Given my understanding is that they choose an interest at random to satisfy only from that list, the idea is to hit as many of those as cheaply as possible. Just about everyone has relaxation as an interest. Social and shopping were also common, though usually only of those two. Given I hand picked a number of colonists and many of them had traits like fit or rugged, there were a good number with exercise as an interest too. Other interests were more random and rarer. Children all have playing as their only interest, at least to start that I can see.
Which buildings then are best? All of the parks give relaxation, playing, and exercise. Given that they're cheap and have zero maintenance, I'd think 3 or so tiles at least are mandatory. 40 isn't the best comfort rating, but it's solid. Given you need a diner or grocer, that settles social or shopping. Diner looks like the better solo thing to grab, but grabbing the grocer + casino complex hits the most by far. Spacebar + grocer is cheaper, but doesn't seem quite as good, especially if you avoid recruiting alcoholics. But the casino is pretty expensive. Diner seems much better as an option if you're low on resources and want to make the most of your limited space. Grocer + gym also looks to mostly fit if you're looking for the benefits the gym can provide.
Foodwise it looks like ~.2 food per person per sol? I know I have some gluttons and I won't be surprised if there was some different math involved, but it's close enough for a ballpark answer. Leaf crops in the hydroponics farm gives 2.5 food per sol, times your workplace bonus looks like. One for every 12.5 people, plus enough for a food surplus if it's staffed with happy botanists.
Beyond those requirements, you'll probably want an infirmary if you're looking for kids, plus a nursery. Looking at the layout, that means I can have a nursery, infirmary, grocer, casino, two residences, a research lab, two hydroponics, 2 single tile gardens, and a machine parts factory. Which seems solid for a first dome.
And most of that is to allow for kids. You need at least some comfort or the colonists get upset and leave. Plus it improves morale which improves work speed. If you're not worried about producing more kids and grabbing applicants instead, you can lighter on the comfort buildings.
That's all if I understand things correctly. The documentation is...lacking.