As a data point for stress in 47.05..
I created a world with dwarves, elves, and humans. One dwarven civ, and 20+ each for elves and humans. Pop cap and strict pop cap of zero, so no migrants, and 7 total dwarves for the entirety of the test.
No demons, no HFS, no goblins, no necromancers, vampires, titans, semi/megabeasts, forgotten beasts (didn't breach the caverns), or anything like that. No personality, preference, skill, stat, or speed adjustments. Just the starting seven, with all their random flaws and preferences.
Embarked in an Untamed Wilderness, set up a trade depot, and waited.
Set up a farm, a well, and some (glass improved silk crafts) industries to sell to the traders.
Elves, Humans, and Dwarves, all arrived in their seasons, as expected, and trading with them was successful.
Repeated this for 5 years.
Stress levels are all zero or less, according to Dwarf Therapist, after five years.
The dwarves had: A large tavern. A well. A large dining room. Beds. Access to a variety of booze. Prepared meals. A local king who took that position after the first year. Mugs. Chairs. Tables. Manager, Broker, Bookkeeper, Expedition Leader.
The dwarves did not have: Individual bedrooms, a dormitory, any bedrooms at all, statues, instruments, animals/pets, a place to worship/pray, a militia, hammerer, sheriff, or chief medical dwarf.
Happy to upload the world/save if anyone is interested, but it seems like satisfying at least some of their major needs for many years is sustainable up to at least 5 years. In the past, this same experiment would typically result in at least one tantrum-ing, melancholy, or similar leading-to-death mental illness, depression, or anger situation in less than 3 years.
I'm going to continue to run the fort for over ten years to see if anything significant changes, on the stress side of things.