You can catch all of them, but if you're saying which one you should catch with a masterball, I would save it for Diagla or Palkia.
No, Mespirit, Uxie, Azelf, and Giratina have no gender. Also Dialga, Palkia, and Giratina created Mespirit, Uxie, and Azelf.
Psiycic
There isn't one.
Uxie, Mespirit, and Azelf are unavailable in Pokemon SoulSilver. They can, however, be traded from a Diamond, Pearl, or Platinum game, or transferred from a Gen III game.
yes
i know mespirit azelf and uxie i have uxie working on mespirit just go into the lakes go to spear pillar for dialga and palkia
lets see....heatran, giratina, uxie, mespirit, azelf, darkrai....yeah
Uxie Azlef and Mespirit don't catch in you have to get the membership card from mystery gift by Nintendo wifi but its not avalible anymore
catch them from there lakes then mespirit will run away so maybe use a materball
spiritomb, uxie, mespirit, azelf, dialga, palkia, manaphy, rotom, and giratina
giratina,mespirit,uxie,azelf,darkai,shaymin,cressellia
Yes, they appear when dialga appears and stop him from ending the world. which then allows you to catch dialga. afterwards mespirit azelf and uxie can be caught at each of the lakes, mespirit will vanish and will tease you throughout the rest of the game.