http://www.pokemonreborn.com/forum/index.php?showtopic=14182 for when Monotype Pokemon are available to you. You can still catch a Burmy (guess that's okay fodder?) and a Budew. I'm... not too sure on Hardcore bosses, but I'd definitely recommend evolving Budew (friendship evolution during the day), as Roselia is a pretty strong Pokemon very early.
For the Magnemite, maybe try stalling it to death with Sleep Powder + Leech Seed?