Also Failed with a group last night but unlike your team we had some debuffs and still couldnt do it. We had
Fire/Rad Controller
Ill/Rad Controller
Ill/Emp Controller
Ice/Rad Controller
Katana/Regen Scrapper
MA/SR SCrapper
Ice/Energy Blaster
and a Fire/Fire Tank
We absolutely tore through every av and mission until we hit the road block of Ghost Widow. We got her down to a sliver once, but otherwise she didnt go under half, and towards the last half hour of the fight we couldnt even budge her hp.
Group even ran to bloody bay to pick up Shivans (there were only 6 of us at this point, the ill/emp and blaster had DC'ed)
The shivans didnt make any difference, GW took care of them pretty quickly even with 3 sets of rad debuffs and her bar barely moved. We tried moving everyone we could except PA from melee range to counter her heal, but it just didnt make any difference, we ended up calling it quits after about an hour and a half of trying.