PARALLAX absorbed the battery and killed most the Guardians. The ones that were left gave all their remaining strength to one and he went to earth to recruit the last GL. Then Parallax did his whole Zero Hour thing and then Hal redeemed himself to take out the Anti-Monitor in the FInal Night.... remaking the sun. The energies left his body and entered Kyle Rayners, making him ION. He released the energies back to the Central Battery, gave the Guardians their lives back, and brought Killowog back to life so that they can recreate the GL Corp. Kyle gave it up because when he was Ion he was omnipotnent and omniscient pretty much and he didnt want to lose his humanity so he chose humanity over power. Thats the story of Ion.
As far as the battle goes:
1. Since Banner has become in more controll of the Hulk personalities inside of him, he generally shows the "Professor" personality. But this form gets hurt often and is limited to his 100 level strength. The only way that Marvel would have a chance is if Savage Hulk was allowed to come out.
2. GL shields have been broken before but it all depends on how strong the will of the GL is, if their concentration is broken, and if they are fighting someone who has greater physical strength than their will. So if Kyle is distracted or his concentration broken, then Thor or Hulk may have a chance at breaking his shield. If not then there is no way.
3. Batman is an awesome strategist. He is underrated a lot fo the time. If he can stay away from fighting Thor or Hulk hand to hand then he would have a chance to monitor their strengths and weaknesses and come up with a plan. Batman gave the entire X-Men a run for their money when he fought them in All Access.
4. Sorry Spiderman fans but Spiderman is out of his league. If Batman is put inside one of GLs shields, he could take Spiderman. He is a more skilled and a smarter fighter. The field would protect Batman from getting KOed by one hit from Spiderman.
5. If Superman could get to Hulk first before he could get fully enraged and hit him hard enough, he could knock him out before the Hulk can do any real damage. I believe he would do so since he has fought Hulk twice once as Savage Hulk and once as Professor Hulk. Professor got KOed in one punch but it took much more fighting against Savage.
I think DC would have this one in the bag. Having GL on the team is too much of an advantage. It would be an interesting fight to see though.