So if Kickback, V-19 pilot, has Debris Gambit and does a barrel roll, can I then link that to a white evade followed by a red lock?

Yup

Just to reference the rule this pertains to.

Rule Reference pg 12

Quote

A linked action can be performed after performing the action it is attached to even if that action was granted by a card effect or other game effect.

Personally, I find this the most important line in the Rules Reference pertaining to this.

"After a ship performs an action with an attached linked action, if the player wants to resolve the linked action, it is added to the ability queue." (RR, Linked Action, p.12)

This is what establishes a linked action as an effect added to the queue like any other effect.

Basically, Kickback performs a barrel roll. Kickback adds the linked Evade to the queue, Kickback adds his pilot ability for a red Lock to the queue. The queue is resolved front-to-back; first in, first out. Kickback performs an evade action, checking for range to obstacles to determine if it is red or white. If White, proceed to the red lock. If you're out of range to obstacles, you'll take a red Evade, then won't be able to perform the Lock action due to stress. Either way, Kickback has to begin with putting both effects into the queue in order.