They'd do fine.
You lose a bit in skill/power/resources replacing Certain individuals, but gain more in others. Overall you're breaking even.
And a MB would (literally) never see Terry coming.
Given Terrific's skill/power set i could see it being written that he could.
Like with Cyborg, it would be a "wow, this character is really stepping up in the rebooted DC continuity" moment for Terrific; that first year in the DCnu was practically made of those.
Not really sure why E-2 GA Wonder Woman wouldn't replace WW. but I agree with Riv. The JSA would handle anything the Nu52 JLA has.
As for Terry Sloane handling the hacking of an MB. We're talking about a guy who not only recognized in seconds that a guy he was fighting was from the Future but also ascertained in those seconds that he was his own descendant and afraid of allowing Terry to die for the risk of erasing himself from existence. Terry made the guy bug out by holding a gun to his own head and threatening to pull the trigger.
He deduced that in seconds with almost nothing to go on. Tet's also look at the fact that the Nu52 Terry Sloane cracked the 9th dimension and knew every weakness Apokalips had.
GA Cap Marvel is SA level Superman. Supes was actually powered up to match Cap from whiz comics who was outselling him (had sales over a million copies per issue). Pre the release of Whiz Supes was only able to leap tall buildibgs etc but his powers steadily rose from march 42 to the point that by 43 he was SA level.
Dr Fate had a lot of energy and matter manip showings in mbps the GA that put him SS level plus his magic and super strength etc. He could TK a planet out of orbit into a sun, and play with time like nothing.
HM and HG actually had showings of super strength beyond the few tons of the modern era (though no explaination as to why)
Flash (jay ) was light speed which in the moder era he's stated a few times he cant do, though has done with speed steal. He could also phase, be completely invisible with vibration and travelled time without a cosmic treadmill.
Alan could do anything a SA GL could, though he stil squarely had the wood weakness that he lost in the 90's. He was also shown to matter manip which modern lanterns havent.
I'd say power wise they were less restricted than SA
Wildcat isn't Batman equal in skill, intelligence or resources.
Hawkgirl likewise isn't WW equal in skill, power or resources.
Hawkman also inst Aquaman equal
CM is close but he's basically SM lite
Finally while I don't doubt Mr Terrific could eventually figure out how to send DS parademon home. I don't think he would survive long enough to come up with the solution.
I doubt they'd be written to lose.
The question for me is, given what we know of how things have gone down, could they feasibly do comparable things. And this team could, given the line up.
OP has stated Golden age versions of each. Ga Cap Marvel was SA S I perman level. He's vastly above anything Nu52 or post COIE Supes ahs ever had to offer.
Anyway, i could see the Hawks replicating the DS eye gouge, and Wildcat slinking around Apokalips same as Batman did, from the JLA first story arc. Those'd be fun to see.
Hard to say. Mr. Terrific series didn't last long enough to reveal the list. The writer in an interview said he would reveal it and said you'd be surprised at who Is #1. I'd personally put DCnU Holt in the top 5 for sure. He was doing some impressive shit.