>counterhit
Also don't underestimate dat invincible head bro. Ness's uair beats like everything from below, and that includes Samus's dair. If Samus is short hop happy you can get under her with a djc uair.
If Samus is more grounded, and pivot fsmashy (which is how I play the MU as Samus), then you might want to use dair from above to get at her, or OVERSHOOT REVERSE DJC RUSH bair/dair maybe.
Ness has the advantage in this matchup IMO, though not a large one
Well I hope you aren't approaching with the fairs themselves. I'm not good at fair chains myself but I guess the best opportunities would be after a lowish-mid percent dair pops them up, or on a tech.