This kind of went on for a bit so if you want to skip it:
tl;dr did a weird cliff embark, my wagon disappeared into thin air, no outpost liaison, although the dwarf caravan showed up. Also I did really dumb stuff.
Tired of FPS death on my elderly, ailing computer, I tried to start a 1x1 embark in a pocket world with a short history. I thought it would be nice to start with cliffs, but found out, bizarrely, that it's impossible to embark on a mountain. There needs to be at least some non-mountainous terrain. Why would it be impossible for dwarves to embark on a mountain?
So I made it a 1x2. Supposedly, there were no trees in either square, but there were actually some, luckily all of them 1 square trunks, since apparently those huge bushy trees are also bad FPS juju. And the embark was actually on the edge of a steep cliff. For some reason, no wagon came along, so I got no wagon wood nor the usual meeting place you get when there's a wagon.
I was amazed to find that the mountain itself was nearly made of lignite, bituminous coal, native platinum, limonite and magnetite.
My general plan was put the trade depot at the bottom, where I can put drawbridges in to close it from either end, so I can keep it closed except when I expect trade, use that as an airlock of sorts, and/or just trap caravans in there and starve them to death until they die and then steal everything. I don't really plan that, but it's a nice option to have, especially if some elven "diplomat" mouths off about me cutting down all the trees while they're here.
Meanwhile, at the top, I can cut down up ramps judiciously, forcing anyone who wants to come up to climb around the mountain every level (it goes up about five), meanwhile I can have fortifications to shoot at them through on each level. Most of my activity is currently on that top level, although I've tried to design it so I can just undesignate all that and leave the military barracks I have currently assigned to overlapping rooms with the dormitory for everyone and the dining room that I also designated as a tavern in the same big room, as well as the throwaway workshops I can deconstruct as I put their replacements on lower levels.
Also there were a few increasingly small levels on the mountain above that largely consisted of coal, so I decided to just get rid of them and mine them all out. Isn't that what coal companies do, often? Just knock off the top of a mountain and go in?
So I designated them all to be mined out.
Now, anyone who has done this can guess what happened next. To say that I have limitations coping with the z-level thing would not be an exaggeration. I have figured out about this underground, and managed to avoid doing this kind of thing much.
Yes, I dug out one of the lower layers entirely before the rest of it, crashing down every layer above directly onto the miners. To increase the embarrassment, there had been a minor "cave-in" previously, which had only caused the dwarf in question to be "annoyed." (There was nearly nothing above him.) So I thought ha-ha, what an amusing mishap, and didn't correct anything, even though that would have been the time to seriously reevaluate what I was doing. Two dwarves died, including a legendary miner who was also the manager and bookkeeper.
On the good side, I don't have to think about what to do with those otherwise pointless z-layers. On the bad side, I'm a complete idiot who literally destroyed much of a mountain out of pure stupidity.
No harm was caused to the main layer where activity is currently ongoing (and where the main entrance to the fortress will eventually be), even though you'd think the top of a mountain collapsing onto it would cause some damage. Dumb luck there.
Oddly, the overlapping main barracks/tavern/dormitory thing has continuously attracted human migrants, from literally seconds after I designated the dining area as a tavern. At first, this was mildly annoying, because a string of bards showed up and then most of the fort did nothing for months but constantly listen to poetry and sing.
Also, I started out with humans/elves/dwarves/goblins as neighboring civilizations, with goblins at war. The only ones of those that currently appear on the civilizations menu, though, are dwarves. The only other civilization is kobolds, with no details, other than that a couple have shown up to steal stuff but run off when detected.
Also, no outpost liaison. I have no idea what's going on with that.