I've been living in NYC for a few decades. So the last time I had to give all that rental info was the same as tvguy. However, when I rented for a short time in CA, a few years ago, they did want extraordinary amount of info.

And yes, they also tacked on all those added fees he mentioned.
What I can tell you is that one law in NYC is: "Possession is nine tenths of the law." What that means is that once a tenant has taken possession of an apartment, (moved his stuff in, is living there,) even if he hasn't paid his rent for several months or is in violation of certain building codes, etc., the landlord cannot just one day, when the tenant is out, change the locks & throw his stuff into the street. He
must go to court and go through a
lengthy court process to have the tenant evicted by the court. that process could take another 6 months or more. So the tenant could stand to lose a YEAR or rent.

$3000/month x 12 months is a LOT to lose. Sometimes the landlord doesn't get back rent back. They just want the tenant gone.
Maybe you can understand why the management companies want to make sure
they aren't the ones being ripped off with a bad, flakey, unreliable, non-paying tenant. So, what understandably to you, are major privacy violations, and possibly identity theft, are basically them protecting themselves. (Again, I don't know what they are asking for now, and if it's all legal.) Even the basics, which tvguy mentioned from 27 years ago, are enough for basic identity theft.
That said, there are unscrupulous types in NYC. Make sure DD actually sees the actual apartments first. That you research that the management companies DO exist and do manage or own buildings. Never give info for an ad you/DD found on Craigslist or in the papers, that wants your credit report & identity info even before she sees & has been in the apartment. Why would they need that even before DD has decided whether she wants it or not?
As for subleasing, I don't quite understand what the problem is. (Feeel free to re-explain it.

) When I first attended to NYU, some century ago, I actually lived with roommates in
better and bigger apartments, for less rent, than the one I am currently in now. I was actually offered the option to take over each lease, for only a
slight increase in rent, versus getting a new apartment at the current market value rental price.
Some of the rentals required/offered adding me as a co-tenant to the current lease, or the landlords would have simply written a new lease in my name with the small percentage increases allowed by rent control laws.
I didn't want to do either. I also didn't want a roommate at the time. I didn't think I needed a bigger space and didn't want to fork over the extra rent for them. I didn't future think.

I always knew I was going to live in NYC the majority of my life.
I gave up those places, looked around, only to find out NEW leases at current market value prices were 1/3 MORE that what I had been paying, for smaller spaces than those I had
already given up. I finally did find a fabulous place and have been rent controlled for decades now. Rent controlled/stabilized places at a decades old rents are gold in NYC.

It also means I can't move.

Not unless I want to fork over significant amounts of money for rent or a co-op and my lifestyle goes back to eating mac & cheese and PB&J for dinners.
In retrospect, as rents overall grew and this place seems to have gotten smaller

, had I known I would be staying in the same place for years/decades, those bigger places, for the more money
at the time, would actually have been a steal comparatively. Even a couple
years later, the same size place at market value prices, were incredibly more than if I had taken one of those original places & paid all the extra rent for a couple years, or the extra deposit, or a "fee" to the current tenant <cough> to make sure I was added to the lease so I could properly and legally take over the lease when they left.
If DD plans to stay in NYC for 3-5 years or more, she might want to rethink what options are available.