I agree with what people said- this MU's a killer.
We should be thinking of Link's advantages.
DI
Reach
long lasting hit bubbles
Power
Combining all these is important. I've never played a good Fox so this analysis is based on data and matches like this:
http://www.youtube.com/watch?v=u45cpzbP6FM
Big advantage we can use: Fox has no range stun. This lets Link space 'tip of attack' and we out reach Fox. Most of our game should be spacing SH Zair, landing canceling moves, and quick ground attacks (jabs, Utilt, Dsmash).
Fox is fast with a reflector and we must approach. Link still can spam safely (relatively) just in a different style. Boomerang deals no damage when reflected, constant attack going out and has good stun at close range- maybe a good retreat aid. Bombs: vertical traveling bombs (up/down throw, dropped, invincibomb) will not have their 'flight paths' changed by reflectors. Explotions cannot be reflected either. These help Link's SH spacing. Zair's easy to throw out for mind games.
DI+Reach: Link's OoS is horrible, Fox and most characters up close murder Link. Link does have amazing DI and disjointed reach. I DI sideways and Zair Falco to prevent follow ups, that might work here. DIing out of multi-hit attacks usually leaves Link able to reach through and hit. Hitbubble/Frame visuals:
Jab 1:
Frame 6: Hitbox out: 4 damage, 2 frame duration.
Frame 7: You can start Jab 2.
Frame 19: IASA. At this point you can do any action, but pressing A will still do Jab 2.
UTilt:
Frame 7: Hitbox out: 9 damage.
--Angle: Blade: 95. Hilt, Arm, Torso: 85.
Frame 12: end of hitbox.
Frame 35: IASA
DSmash:
3 frames until charging. Upon release:
Frame 3 (6 frames uncharged): Hitbox out: 3 frame duration. Angle = 75.
--Damage: Blade = 14. Hilt = 16. Arm = 17. Torso = 16.
Frame 15: Hitbox out: 3 frame duration. Angle = 75.
--Damage: Blade = Hilt = Torso = 16. Arm = 17.
Frame 50: End of animation.
Air Landing canceling attacks:
NAir:
Frame 6: Hitbox out: 10 damage.
--At this point if you land you suffer NAir landing animation.
Frame 8: Damage reduced to 6, hitboxes become smaller.
Frame 27: End hitboxes.
Frame 31: Autocancel
--NAir landing lag has a frame 9 IASA
FAir:
--FAir landing animation can happen immediately.
Frame 13: Hitbox out: 9 damage, 2 frame duration.
Frame 25: Hitbox out: 12 damage, 2 frame duration.
Frame 50: Autocancel.
--Fair landing lag has a frame 10 IASA
BAir:
--BAir landing animation can happen immediately.
Frame 5: Hitbox out: 4 damage, 4 frame duration.
Frame 17: Hitbox out: 7 damage, 6 frame duration.
Frame 28: Autocancel.
Frame 30: IASA
--BAir landing lag has a frame 10 IASA
Zair starts frame 10.
Notice the area covered by Nair; it's big all around Link. I use it as a combo stopper vs Sheik. Frames 6-27 attack and it landing cancels.
Spacing Fox should be the #1 priority.