No, you cannot catch Regirock in Pokémon Black however you can acquire it via migrating or trading. Additionally you will be able to trade for it from Pokémon Black 2 or Pokémon White 2.
In Pokémon Black 2 and Pokémon White 2, Regigigas can be found within Twist Mountain however it won't battle you unless you have Regirock, Regice and Registeel with you.
you catch them
can you TRADE for a pansear on POKEMON WHITE 2!
Technically, no. You don't catch White Kyruem. You catch Kyruem and catch Reshiram. Then the two merge together.
Catch kyurem,catch reshiram, and fuse them with the dna splicers
Imposible.............. Possible with cheats but, you can get it in pokemon black and white 2
You can't
You cannot catch Meloetta in Pokemon Black 2 and White 2. You have to receive it from an event, but as of right now, it has not yet been announced for North America.
Rufflet cannot be caught in Pokemon Black 2, you must trade from White 2 or White.
You can't catch any starter pokemon in any pokemon game. But you can trade them online via GTS.
Heatmor isn't in Pokemon SoulSilver or Pokemon HeartGold. It's only available for Pokemon Black and White and Pokemon Black 2 and White 2.