The decoy is just some guy who'll be disguised as the one that the humanis want to ambush and cripple - one of the rising stars of Urban Brawl on the Arka team. He's there so the humanis won't get the wind of your ambush, and stay convinced that they're the hunters, when in fact the roles will be turned.
As for the info, I'm working on a map, and since Sichr entered the game, I'll prepare an entry point for him as well. You can plan stuff now, using the data below:
1. The terrain is providing a lot of cover - a few crumbling walls of a former Renraku community, a few legally occupied small appartment blocks to the south, a small half-deserted mall in the north, a squatter-ridden old school to the east, and an overgrown hill park to the west. The streets are almost empty, but they're narrow and provide a lot of alternate routes, with dark alleys, backyards and even a proper - but mostly unused - sewer system. From what you can see, it's akin to the worst 'legal' neighborhoods in Seattle. The residents are mostly human, but this place has enough metahumans, and open minded people that it isn't humanis ground. Probably that's why they chose it. The bar is two blocks away, actually, and almost on the verge of the low security zone. You can see where the neighborhood turns from low-life to proper corporate, but as far as you could notice, this one has a different security service. The local Knights Errant don't cross the district's borders.
2. The goons are mostly small time hooligans, and petty criminals. They're mostly on the record - either KE, or someone else's. Most of them have debts, and beating metahumans let's them both vent their anger, and empty their pockets. You can see the weakest link - two humanis-born kids, both of them barely sixteen, none of them on record, just data the girl sent saying that they're also forced to do this. You have gathered six vids and photos of the targets, with the boyfriend being most recent and useful. He's going to be one of the goons, and not happy because of that, as he usually leads this rabble. The two elite humanis are known for murdering metahumans in cold blood. One of them - called Fishman because of his cold eyes - gutted a troll girl who wandered into the wrong alley, and the second one, who's called Adam (not his real name, he just has the 'pure human' look) is more of a backseat murderer - he usually forces others to do his job, preferably other metahumans to 'prove their savagery'. You couldn't find what kind of warez they have, but 'Adam' is obviously gene-engineered and bio-sculpted, and comes from a wealthy family of Horizon midlle managers. You'd be very surprised if he wasn't enhanced with bioware in every way he could.
Gel rounds are perfectly legal, if you have a gun permit. You can buy them in a shop, or just ask any of the street-peddlers for them. Roll for Availability 4R, Charisma+Etiquette, 1 hour, if you want to hide the fact you're buying them, and look on the streets.