maybe even a swimming pool with the water being considered a reserve fuel supply.
absolutely not no how no way. lose gravity and everyone in the space is in terrible danger of drowning.
I guess redundant grav and emergency water removing systems (with independent batteries for power, as we're talking about emergency systems) could allow it. After all, this could only be posible in the larger cruisers, due to its sheer volume...
The observation lounge can be equipped with high tech view screens for use during jump, They cover the observation windows and instead project totally perfect images of whatever you want.
IIRC in MT:SOM was said that most staterooms (not only observation areas) were usually equiped with holographyc projectors to allow the passengers to decorate it at their taste.
As for the observation area, I'd think a good idea would be some kind of panoramics from the destination planet, just to allow the passengers to know a little about their destination.
Another ammenity that uses t obe in most cruisers today is steticien care (massages, hairdresser, etc.) that could also be used to adapt your look to the destination planet.
Remember that you will leave the ship on a different planet (not only country) tan the one you took the ship in, with not only different culture, but also probably different gravity, atmosphere, and even sunlight wavelengths, and I also think that the time in jumpspace could be also used to adapt people to all that (by gradually altering all those factors). In fact, in MT:SOM this adaptation was given as standard practice for gravity.
And I'd expect videogames (or hologames) in a passenger ship to be state of the art, as boredoom might be a true problema when you're enclosed in such small space for several days.
Even so, I'd expect most of the entertainment would be social interaction (dinners, dances, etc...).
We must think that in those ships, unlike today's cruisers, the goal is to reach the destination (something now usually done by airplane), not to enjoy the trip. In this sense I'd expect them to be more alike from the Titanic times than to nowdays pleasure cruises.