How old is Chloe? She sounds like a relatively normal, rambunctious, and, yes, rude adolescent. Also, what breed is she?

Hate to say it, but Chloe sounds leash reactive. When Ivy was 6-ish months, she started lunging after dogs (on lead, never off lead), too. This was after nice loose leash meetings with the other dogs, as well. The fact of the matter is that Ivy lacks the right doggy manners to properly incite play. Plus, she is very high energy and driven. So when she is restricted by the leash, she converts the excitement into frustration (aka lunging and barking). This is essentially leash reactivity. She is by no means aggressive, but she is certainly reactive and had a very low threshold (note the past tense . It sounds like Chloe's threshold is actually pretty high, so find a few bombproof dogs you can borrow as demo dogs. On a loose leash, allow Chloe to walk within a few feet of the dog, click/treat. You should be behind her so that she has to trot back towards you to get the treat. Repeat repeat repeat. If you sincerely think Chloe has the right skills to calmly meet the other dog nose-to-nose, you can start training that, too. I, however, know that Ivy is incapable of meeting other dogs nose-to-nose and so we just click/treat for looking at the other dog (Look at That! game coined by Leslie McDevitt from her book Control Unleashed).

Frankly, I think Chloe just needs to be taught the right lessons from your own dogs. Blackie actually sounds like she's acting like the perfect matriarch. To ensure safety, though, muzzle all dogs whenever they interact in the yard. Giselle endures a lot of crap from Ivy, but, if Ivy pushes Giselle too hard, Giselle will give her a warning scruff grab. After that, Ivy will hunker down into a submissive bow. At that point, I usually redirect Ivy and give her something more wholesome to do (fetch, obedience, agility, a hard jog, etc.). I want Ivy to learn her boundaries and to be aware of them. But after a correction, I want to set her up for success, so I redirect her and give he an alternative activity.

Also, I have not gone to conventional dog parks for a few months now. The only places I take Ivy now are off-lead hiking trails, and she is ALWAYS 100% under voice control. After a brief <10 second meeting with a dog, I recall her and keep moving. That way, she stays below her threshold and maintains relatively "proper" doggy meeting manners.

ETA: If, at any time, Chloe does not respond to the click, she's above threshold and you need to take a few literal steps back.