1) Either:
a) In the Civilizations tab of the launcher, check only the race you want to play as under the "Fort" column (so the other races, e.g. kobolds, have an X); or,
b) If multiple races are fort-enabled, use the "neighboring civilizations" list in the embark screen to see what race your select civ belongs to. The first race in the list is yours.
2) The launcher isn't complete for the new version yet so there's no easy toggle to remove aquifers. You can go into the raws to remove the tag yourself, though. Most of them are inorganic_stone_soil, though some are in _stone_layer, _stone_mineral, and fuel_masterwork. Just ctrl-f [aquifer] and delete any instance you find. According to
the wiki this can be done before or after a world gen, but make sure you're editing the right files in either case (raw/objects/ if you're going to gen a new world, data/save/[region] if you're modifying an existing one).