I want to remove Hydralisk Attack as an actor and replace it with a different actor. How do I unlink the current actor and link a different actor to this weapon?
Select the Hydralisk Attack actor in the list of linked Objects, then press Control-Alt-E. A small box will appear below the list showing how that actor is linked to that weapon (including which particular field(s) are used to establish the link, and any intermediate linked objects) - from there, it's just a matter of modifying that linking field to suit your new actor
In the case of the link between Weapon - Needle Spines and Hydralisk Attack, it's occuring in Hydralisk Attack in the Events field although I'm not sure if you can unlink that without adding your own custom objects (i.e. a custom Hydralisk Attack actor which links to your custom Needle Spines weapon and custom Launch/Damage effects)
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.