Here is my take as a frequent Amtrak traveler with Select Plus status. Book the bedroom but make sure you call Amtrak to do this. A bedroom used only for sitting can be booked with 4 people in it, but you can not do this online. Your going to have to book another roomette for the 5th person or you might even ask the Amtrak agent about the family bedroom and if they allow 5 people in sitting configuration.

Booking the rooms will get you 2 meals per person, lunch and dinner included up to San Francisco. I'm not sure if they are currently running the Pacific Parlor Car on the Coast Starlight, but if they are, then you also get exclusive access to it as a sleeping car passenger.

Book the Amtrak bus option, since the connection is guaranteed, or choose Emeryville since the station building is clean and modern and a better neighborhood than Oakland. Also, there are hotels right across the from the Emeryville station if needed. There is a pedestrian bridge to across into the parking lot of the hotel / shopping area.