This world and embark matches most of your requirements, save two. There are only a few megas/semi's, but you can adjust that as you wish, and the Dwarven Civ is Dead (not dying) with Human and Elf neighbors.
Other than that, the embark is split evenly three ways, and has reanimating Terrifying, Joyous Wilds, and Untamed Wilds, with a Spring & Brook, and is steel friendly.
As always, now that the geography/geology part is done, you can regenerate for different civs by randomizing those seeds.
As a bonus, the good and evil flora is quite dense, in this embark location. Lots of eyes, tendrils, bulbs, etc.
worldgenCreated in DF v0.47.04.
[WORLD_GEN]
[TITLE:AELWEN1]
[SEED:S2ioAWI6cEkQkaS2oAmQ]
[HISTORY_SEED:iOOma2IweYuYSC6mc4Gk]
[NAME_SEED:ssEGw6uw2oeqsWI88U0u]
[CREATURE_SEED:euaeWUi02uUGoyys6oiq]
[DIM:17:17]
[EMBARK_POINTS:0]
[END_YEAR:200]
[BEAST_END_YEAR:200:-1]
[REVEAL_ALL_HISTORY:0]
[CULL_HISTORICAL_FIGURES:1]
[ELEVATION:220:220:0:0]
[RAINFALL:0:100:3200:3200]
[TEMPERATURE:25:75:3200:3200]
[DRAINAGE:0:100:3200:3200]
[VOLCANISM:0:100:0:0]
[SAVAGERY:0:100:3200:3200]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[POLE:NONE]
[MINERAL_SCARCITY:100]
[MEGABEAST_CAP:2]
[SEMIMEGABEAST_CAP:4]
[TITAN_NUMBER:0]
[TITAN_ATTACK_TRIGGER:0:0:0]
[DEMON_NUMBER:0]
[NIGHT_TROLL_NUMBER:0]
[BOGEYMAN_NUMBER:0]
[NIGHTMARE_NUMBER:0]
[VAMPIRE_NUMBER:0]
[WEREBEAST_NUMBER:0]
[WEREBEAST_ATTACK_TRIGGER:0:0:0]
[SECRET_NUMBER:0]
[REGIONAL_INTERACTION_NUMBER:1000]
[DISTURBANCE_INTERACTION_NUMBER:0]
[EVIL_CLOUD_NUMBER:0]
[EVIL_RAIN_NUMBER:0]
[GENERATE_DIVINE_MATERIALS:0]
[ALLOW_DIVINATION:0]
[ALLOW_DEMONIC_EXPERIMENTS:0]
[ALLOW_NECROMANCER_EXPERIMENTS:0]
[ALLOW_NECROMANCER_LIEUTENANTS:0]
[ALLOW_NECROMANCER_GHOULS:0]
[ALLOW_NECROMANCER_SUMMONS:0]
[GOOD_SQ_COUNTS:70:0:0]
[EVIL_SQ_COUNTS:70:0:0]
[PEAK_NUMBER_MIN:0]
[PARTIAL_OCEAN_EDGE_MIN:0]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:25]
[REGION_COUNTS:SWAMP:0:0:0]
[REGION_COUNTS:DESERT:0:0:0]
[REGION_COUNTS:FOREST:0:0:0]
[REGION_COUNTS:MOUNTAINS:0:0:0]
[REGION_COUNTS:OCEAN:0:0:0]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:0:0:0]
[REGION_COUNTS:HILLS:0:0:0]
[EROSION_CYCLE_COUNT:1000]
[RIVER_MINS:0:0]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:0]
[SUBREGION_MAX:5000]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:100]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:0]
[CAVERN_LAYER_WATER_MIN:25]
[CAVERN_LAYER_WATER_MAX:50]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:0]
[LEVELS_ABOVE_GROUND:8]
[LEVELS_ABOVE_LAYER_1:20]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:1]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:1]
[CAVE_MAX_SIZE:1]
[MOUNTAIN_CAVE_MIN:0]
[NON_MOUNTAIN_CAVE_MIN:0]
[ALL_CAVES_VISIBLE:0]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:20]
[TOTAL_CIV_POPULATION:0]
[SITE_CAP:3]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:0:0:0]
[RAIN_RANGES:0:0:0]
[DRAINAGE_RANGES:0:0:0]
[SAVAGERY_RANGES:0:0:0]
[VOLCANISM_RANGES:0:0:0]
[PS_VL:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:100:100:100:100:100:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_VL:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0]
[PS_SV:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100]
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[PS_SV:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100]
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[PS_SV:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100]
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[PS_SV:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100:100]
[PS_SV:0:0:0:0:0:100:100:100:100:100:100:100:100:100:100:100:100]
[PS_SV:0:0:0:0:0:100:100:100:100:100:100:100:100:100:100:100:100]
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[PS_SV:0:0:0:0:0:100:100:100:100:100:100:100:100:100:100:100:100]
[PS_SV:0:0:0:0:0:100:100:100:100:100:100:100:100:100:100:100:100]
embark