All officers (as well as a few NCOs) have cabins, while the ratings are in dormitory or barracks set ups depending on department/rank/location/importance/etc. Middle-officer cabins often have a separated bedroom, quickly becoming akin to small 1-bedroom apartments. Upper officer cabins are typically 3-4 room affairs, and are designed with attached steward quarters. The Captain would have the large end of this (3 larger rooms, maybe 5) and room for a couple of stewards/assistants. As Rogue Trader, you have what amounts to a mini-mansion, designed to potentially support a family with all noble comforts (study, withdrawing room, dining room, sitting room, etc). As this was once a Navy Vessel, those familiar with navy construction (of if you do a little research), one can tell some upper officer quarters were expanded post-navy, the Captain is in the Navy Captain's Cabin, and the Rogue Trader's Cabin was constructed entirely out of an unrelated section. (Also of note, the astropaths have a tall tower at the top of the bridge to help remove them from the telepathic 'noise' of the rest of the crew, and the Navigator has a large cabin-office-observatory-cartography studio complex off to one side of the bridge.
Inter-ship communication can happen a couple of different ways. There is a wired phone network that runs through a servitor (cyborg-droid) operated switchboard for direct communications. There is an overhead page system (that can be limited to particular sections) and video-feeds to main public areas. (This would be how you gave your speech to the crew, this is also a post-navy add on). Lastly, you can always call for a kid to run a message for you.