I'd really like a normal Marowak, not the Alolan form. I tried leveling up a Cubone to level 28 during day time and nothing happened, does this mean it's impossible to get an ordinary Ground-type Marowak in-game?
When you transfer Pokemon from previous games and breed them, you will get their Alola Forms. However, if you attach an Everstone to the non-Gen VII native variant and breed, you'll get the standard form. You cannot evolve standard Raichu, Exeggutor and Marowak in this game.
Source.
Sorry, you're out of luck.
You must transfer a Marowak from previous generations.
Read this answer by Pokemaster on the topic in the Pokebase for more information.
No. You'll have to wait until you can buy pokebank in a few weeks.
This: http://www.pokemon-sunmoon.com/en-au/pokemon-bank/ and this http://pokemondb.net/pokedex/marowak