Hi Alex,
1) Lubo is correct, go ahead and upgrade NPM first. After that it shouldn't matter.
2) WPM should have an RC shortly (likely next week), so it wouldn't be broken for long. I'm not sure what the behavior is exactly when this happens, but pretty sure it doesn't keep from working forever.
omri - Can you provide more details of what the behavior is with WPM 2.0 or 2.1 with an upgraded Core?