Does the Ravastra Skirmisher's "Interference" ability stack?

also, is the ability effective on all units in a given radius, or is it targeted? also, is it channeled or non-channeled?

No. (Also, you can download the textual version of the reference files converted by Harpo9999 from http://soase.weebly.com/convertdata.html)

From the Interference BuffCrippleAbilities.entity:
stackingLimit 1

Enjoy.

Applies the buff to a single Target (Frigate or PlanetModule) with a range of 6000 and it's not channeled.

AbilityCrippleAbilities.entity:

buffInstantActionType "ApplyBuffToTarget"
instantActionTriggerType "AlwaysPerform"
buffType "BuffCrippleAbilities"
targetFilter
 numOwnerships 1
 ownership "Enemy"
 numObjects 2
 object "Frigate"
 object "PlanetModule"
 numSpaces 1
 space "Normal"
 numConstraints 1
 constraint "HasAntiMatterPool"
range
 Level:0 6000.000000
 Level:1 0.000000
 Level:2 0.000000

thanks very much