S.S. United States to return to active commercial service

This would be fantastic but don't hold your breath or don't contact your travel agent just yet.

The parent company of Crystal is the Genting group, the entity behind the destruction of Bimini and the bimini super fast ferry fiasco, which went out of business just a year after they built a massive 1000' pier on a pristine beach and reef.

Along the way, they tried running illegal gambling cruises to nowhere using foreign flag vessel and crew, claiming to a federal judge that this was the only way their operation coudl survive...

I agree; the chances of this actually happening are slim to none - for a variety of reasons: logistical, engineering, financial, and commercial.

Even if crystal goes ahead, the topsides will be drastically altered to create more staterooms and balconies. Looks even worst in the drawings that what NCL did to the France.

Today I was surprised to see the Bimini superfast is still tied up at port of Miami over a month after genting cancelled service. I would have thought it would be sold or used somewhere else

Not wanting to be packed into another super sardine can, toes getting steeped on in every chow line, ammonia in all the pools, a floating sub-sea of open mouths competing with the screamers (brats) and other big crowd problems. If I wanted more of this abuse, I'd go back to Disney or other packed people abusing parks.

For the traveler not in a hurry, I can see some business like the ICW cruisers or coastal tours. Luxury, slow, Period furnished cabins, proper high end meals, relaxing atmosphere and no hurries. AND, relaxing on a historic ship as the SS US that does not need to defend her speed runs from long ago. Even I would consider a ride.
Yes, I think there is a niche. Money maker; not for a very long time.

There is no as is or original layout as she is an empty shell. Everything inside was gutted years ago incl staterooms, walls, etc

All the interior hardware was sold off. That may have be a short coming. All that period hardware is going to be hard to replace (replicate?).
Remember, the original interior was fire proof yet still elegant.

Here's a site that has what seems to be original deck plans, along with ideas for converting the SSUS to a floating museum (same site has a similar plans and ideas for the Queen Mary).

www.sterling.rmplc.co.uk/ssus/

Refurbishment of the SSUS would likely have to include the same changes as were made to the France: take out 2 of the 4 shafts/turbines/boilers to reduce operating costs (but also reduce top speed), add as many "modern" amenities as possible including adding a few decks of suites (but spoiling her profile), get rid of the strict separation of the classes.