You can ignore this or set the password to anything you want. If you do set it you will be asked to enter it after you exit the authentication page. It is mainly there for people who want to install HP on a public server so your home is protected at least with a simple password. If you leave it blank you won’t use it at all and it can be safely ignored.
This is the URL for the SmartThings cloud server. For US people this is typically https://graph.api.smarthings.com
It is something different for EU people. For Hubitat hubs this is something different that doesn’t apply here.
It is actually mentioned in the documentation - but there is alot there I know so it is easy to miss. Anyway, this is used to bypass server auth. On the first auth pass you won’t know this. For new users you can ignore it.
Same as above. Ignore for your use case.
This is not a user provided value. HP creates it and will show you the value here. It is used if you want to use HP in expert mode as an API. It is documented near the end of the doc file.
Same as above, you can ignore this if you aren’t using HP as an API.
Regarding your questions about video - yes you can use your camera to feed a video tile. This isn’t well documented and is buried in community provided examples further up in this long thread. Let me dig it out and get back with you. I don’t use live video feeds but @cwwilson08 does so he may have an example he can share.