Get Good Listener through multiple playthroughs

You do not have to fill in all the empty spots to win this achievement. You also will have to do 2 run throughs to be able to collect enough nodes to do this. Everything carries over on your 2nd play through. You can find some guides for the 360 version at least on True Achievements

Yes. Most achievements and challenges are cumulative across all playthroughs and modes. The achievements relating to collectibles (Gotta find 'em all and Nearly there) seem to require using a single character, but you can repeat the campaign with a character in single-player mode, which keeps your skills and inventory intact, including all collectibles you've found, so you can use that game-plus to get the rest of the items you missed the first time through.

Also, the challenge relating to collectibles (My collectibles, let me show you them!) does count total collectibles across all characters, and they do not have to be unique collectibles. (Example: If you get Banoi Herald excerpt #1 with all four characters, that will count 4 toward the total of 140; you do not have to find 140 unique collectibles across all four characters.)

Note that this gives you an easy way to level up a new character: get to 90% or more on a Level 4 challenge with a high-level character, get to a checkpoint to save your progress, then load a low-level character and complete the challenge. Because the experience reward does not scale, a reward that might not change a level-50 character much can boost a level-5 character several levels.