The Jaeger would struggle to get a hold of ironman flying at speed, who i think could crack open the visor from a distance. Then blow up the pilots. As well as this, thor could be flying around, damaging it with lighting or throwing mjolnir at its legs. Also i think with their agility Hawkeye or black widow could scale it, blowing up its joints. I think the Jaeger would strugle to locate them as it only has te visual from the visor. Hulk could also go to town on its legs as, again, the Jager was losing track of the Kaiju i think it would struggle to keep up with him.
The Chitauri army from The Avengers vs 6 horror movie villains of your choice.
No reality warpers-No Loki
Horror characters have knowledge of The Tesseract and The Scepter, which is hidden in the city. Civilians are in the city, but the teams goal is to defeat the Chitauri, not protect the city, so collateral damage s a non-factor.