For Reshiram, I think you found a great move set, but there are moves that I think that are unnecessary.
> 1) 2 Dragon Moves aren't serving you anything except more PP. Especially seeing that the stronger move "Draco Meteor" is basically weakening every time you use it (loss of SpA)
2) A strong fire type move that's trading off 30 base attack for 15 accuracy. In a way, this might be better if you love taking high risks for damage. Otherwise, take fusion flare since both fire moves have 5 PP, and you know you will hit every time with fusion flare.
3) A single fighting type move with very pretty low accuracy might sound terrible, but it's like the only fighting move he can learn - oppose from rock smash.
So, I think your finished move set should be this:
- Fusion Flare
- Dragon Pulse
- Focus Blast
- Earth Power
I chose Earth Power to finish it because it provides 3 extra type effectiveness plus the balance of his rock weakness - while still being neutral to the others. The other moves provide a great use of STAB and type effectiveness while still being strong.
For the EV spread, there are two possible choices:
252 SpA / 4 SpD / 252 Spe
> This spread strengthens all of his moves category while still making him a fast sweeper. The other 4 EV was uses to slightly strengthen his defense.
64 Def / 252 SpA / 64 SpD / 64 SpD
This spread strengthens the special attack category - for all his moves. The rest gives him good speed and defenses for battling.
This is pretty much my opinion, but your choice. A good nature for him would be either "Modest or Timid" with any item of your choice. Hope I helped! :)