Out of the chronicles games, I think you should get Darkside Chronicles. You go though the exact same events from RE2, Code Veronica, and a new scenario entitled OPERATION: Javier. Some twist include that Claire and Steve had to go through a training area where they had to shoot targets and zombies, Wesker never appeared or fought, Alexander first shows his face and in a video about his daughter becoming obsessed with the Veronica virus like the brat she is and tells you to destroy her, and of course it shows Steve falls and his axe gets into him. You even get to see how Leon was recruited into the goverment. OPERATION: Javier also answers questions on how Krauser turned into an enemy in RE4. Plus you even get to hear his thoughts on how he thought during the last few missions.
In Umbrella Chroincles is you of course do 0,1, and 3, plus a mission where you fight Umbrella in Russia. It shows how Wesker got out of the facility, how Rebecca got into Mansion (but it never showed how she got into guest room outside the Mansion), how Wesker survived and how he got out, and how Ada survived (but not the full thing). In the new scenario which I forgotten the name, it shows Jill and Chris in a Russia facility trying to stop the BOW. Also in the game you meet a guy named Sergi, or whatever, and all I have to say about him is that he is weird. He really is, all he dose is cut himself with some sort of blade. Everytime I see him do that I always ask, "Why dose he keep doing that?".
Out of my opinion, Darkside Chroincles is much more better and answers more important qustions.