Hate to break it to you, but it's unlikely anyone will be interested in those legendary Pokemon. Most people want as close to flawless as possible, (including a usable Hidden Power type like Ice or Grass for Raikou) and a Gentle nature is generally not desired on Mesprit. If you still have some legendary Pokemon left to catch in your game, why not check out Buckert's guide on soft resetting to get yourself ones that will be much more desirable?
Net works fine, though Master could be cool if you're able/willing to try and DexNav one in the Safari Zone.