I finished breaching the aquifer.
Made a slab for the inaccessible dwarf corpse, so now all spirits are at rest.
Found two caverns and magma, which is good since the few trees I've cut down were not regrowing fast enough to support a metal industry. Or much of anything else, for that matter.
Total cost of the aquifer was 7 corpses, 4 drowned dwarves and three more dead of moods requiring stone, which is perhaps the most costly start I've ever seen, for starts entirely devoid of noteworthy combat. First mood after I had access to stone? Required no stone. I can tell the game is taunting me.
My fort's gotten much more population, so I suppose I'll have to deal with the little things I've neglected (move the farms, assemble 2-3 squads, make a tavern, some temples, make some bedrooms, make beds, build traps galore, archer turret, lever controlled entrance, etc). My dwarves are currently hurting for happiness, but I should have things put to right shortly.
Learning not to get distracted while trading. Now I need to sort out how to easily get corpses out of cages.
Oh, and there's gobs and gobs of metal ores, by the looks of it. First stone I found was magnetite ore, and the first layer I deemed safe for digging (I never setup one level below aquifers) is a flux layer. Digging for lava I found an incredible variety of ores. Should make for a viable defense, once I have unwelcome guests.