I've been looking around in the editor and the only field I can see about add-ons and such is pertaining to Terran add-ons (I think?).

Any help with this would be much appreciated.
Side question: What's a blue field represent? I know gray is unedited and green is edited.

I do stuff and thingies... Try widening and reducing the number of small nooks and crannies to correct the problem.
blue is sc2liberty data.
gray is core data.
green is map data.
Alright, thanks for that.
Main question still unanswered.
I don't know if it's even
possible, yet, to attach things in the data editor. It may just be very hard to find...
BUT, I did see some trigger functions like "Attach actor to unit". I can't recall exactly, as I am on my laptop right now.
None.
I'll look into that, I never thought about triggers. Didn't think you could do that stuff with those, lol. I keep forgetting it's the WCIII editor.
I believe "turrets" are units attached to units, I'm a little fuzzy on turrets, but you might be able to duplicate one, give it the model you want, and attach it to a desired
unit, but I'm not sure this is possible
None.