Nacrene City, if I remember correctly...
you start the game at nuvema town
A girl in Undella Town.
SHE IS IN UNDELLA TOWN 1st house next to the pokemon center
go to the battle subway and it will be there
go to the giant chasm near laconusa town and vs him
you need to revive it's fossil in Nacarene city's gym's museum's front desk
Eterna.
you revive them in the town of oreburgh in the scientist's building
thats not a town.
You could use a revive, max revive or go to a Pokemon centre (one in every town or city). Going to a Pokemon centre will also change the pp of all of your pokemons moves to full. If there are no Pokemon centres around - you coulkd use a berry (like a leppa berry).
Beat the Pokemon league!
Sazanami Town is actually Undella Town.
Nuvema Town
you get it at a town in Pokemon black
it is kyruem
Fossils turn into Pokemon like cranidos, shieldon, aerodactyl etc. Revive them at the mining museum in Orburgh Town/City.
N is not located in Anville Town.