How is “1 bed in 4- bed dormitory room -female only” different from “1 person in 4-bed dormitory room - female only” ? And do I have to share the room with other people if I book one of those rooms,

One way or another sounds like a party.

I don't think those are different. The dormitory room, yes, you would share with other guests. I have stayed in one of their (mixed) dormitory rooms before, there was a large lockers for your possessions if you're concerned about valuables (bring your own padlock). It would fit a medium size suitcase easily enough. The beds are bunk beds but very sturdy and comfortable. It's more comfortable and nicer than a typical hostel dorm room.