The lynchpin of this strategy is Nightmare. It has a long disable time, even at low levels, and even inflicts a little damage (20 per second). It also makes it very easy for Light Strike Array to hit. Both heroes have a reasonable ranged attack too.
The big problem with Nightmare is that you can't auto-attack someone under it's influence without it transfering to you...HOWEVER, you can still target the person with spells...
Assuming both players max their nukes, even without their right clicks (safe to assume you would get a few in as the enemy tried to retreat):
- At level 2 their combo has 360 damage (270 MR)
- At level 4 it has 580 damage (435 MR)
- At level 6 it has 1660 potentially (1245 MR)
3 levels in Dragon Slave = 230
2 in Light Strike Array = 150
3 in Brain Sap = 230
2 in Nightmare = 100 (5 x 20)
1 in Laguna Blade = 450
1 in Fiend's Grip = 500 (5 x 100)
Plus a total of 11.6 seconds of stun/disable that you can split over both lane opponents. Usually you Nightmare one, and Fiend's Grip the other, Lina can use whatever combination of auto-attacks and nukes she likes, as both will be disabled for 5 seconds. It's also quick to initiate - Bane just pops off the relevent powers. Obviously Arcane Boots are a big help here.
Obviously you have to account for magic resistance, but when you consider that you also have 3 stuns/disables included in that, the opposition better be seriously tanky...