There are three ways to get a second Reshiram. One-You can buy a second "Pokémon Black Version" or "Pokémon White Version 2" and transfer it from there. Two-If you are a hacker, you know what to do. Three-If the Pokémon Company are holding an event to get Reshiram, well, you have your solution.
dito evolves into reshiram
You don't find Reshiram in Pokemon White. You can only get Reshiram in Black.
reshiram does not evolve
No, Ash does not capture Reshiram.
no ditto and reshiram both do not have genders
No. Reshiram is a Black only Pokemon.
No, you cannot make a Reshiram Egg.
Reshiram is not in pokemon white, Reshiram is in pokemon black however you can trade Reshiram over to white. Instead of Reshiram you get Zekrom near end game
Reshiram is genderless, but is designed to be like a female.
Reshiram is not in White. You can only find it in Black.
I would say Reshiram. Other people would say Zekrom and others would say Reshiram.
You can link Reshiram with Hideyoshi (Warlord who owned Ignis & has a Chimchar/Monferno/Infernape.) He can link with Reshiram.