
My doberboy barks at everything that goes past the front window - and the one thing I've learned is NOT to punish them; no shouting, no spray collars. The best thing I find is to either tell them it's okay in a calm, happy voice then lead them away from the window and distract them; or to say "good girl, that's enough" then again, distract them. Do bear in mind that dobes are guarding breeds - warding off trespassers is second nature to them, whether those people are actually on your property or just walking past.
Remy also used to go nuts - and I mean nuts! - at people walking past if we were walking up the drive heading out for a walk - I did use to correct him for this, either shouting at him or a little smack, but he got worse; since I started distracting him, and praising for attention to me, he has improved dramatically, and hasn't even grumbled at anyone going past in at least 6 months - even if we are standing at the very top of the drive and someone who he's previously had a go at has walked right past his nose. Even his reactions to Jet - his arch-nemesis collie from down the road - have gotten markedly better of late, just with well-timed praise and titbits, and ignoring bad behaviour.
Corrections only serve to make it worse; far as I can tell, as with correcting a dog-aggressive dog, they associate any and all unpleasant events with whatever they are focused on - so when your girls get a spray when they are trying to ward off a stranger, they associate the spray with that person, and will most likely be worse next time.
Keep a close eye on both girls though - same-sex aggression is seen in many dobes that live together; much more so the boys, but it is seen in the girls too, and you've already seen some redirected aggression (that is, frustration from not being able to get at people outside - or the annoying neighbour - being directed on to each other as fighting).
There may be other issues at play here, and I'm sure someone else will be along with their own thoughts and feelings - someone with more experience in these situations than me and my one territorial boy, I just wanted to tell you how I've dealt with a similar problem. If there's any way you could keep a record of the moron who's teasing your dogs it might help in the future, but that's not my area of knowledge!