HomePod and Apple TV which serve as AirPlay targets are typically available to any device on the same local network. They may optionally require a passcode to connect if you set it up that way. AirPlay doesn't allow remote viewing of an iPad screen.
From Manage AirPlay settings on your Apple TV - Apple Support:
Go to Settings > AirPlay. From here, you can turn AirPlay on or off. You can also choose who can AirPlay to your Apple TV:
- Everyone: Anyone can see and AirPlay to your Apple TV.
- Anyone on the Same Network: Anyone connected to your home Wi-Fi network can AirPlay to your Apple TV.
- Only People Sharing This Home: People that you invite to control your home in the Home app can AirPlay to your Apple TV.
- Require Password: A password will be required before anyone can AirPlay to your Apple TV.
The options are similar for HomePod.
I don't know why Bluetooth might have been enabled on your phone if you've previously turned it off, but you would typically want it available if you have a HomePod, AirPods, an AppleWatch, or on your iPad if you have an Apple Pencil. Again merely having Bluetooth enabled doesn't mean that people sharing your Wi-Fi network have access to the content of your device.
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