Take acounts off

If you remove your friends account and create your own, then anything in the Ready to Install area re your games.

If you have an external HDD, yo could move all the games to that then unplug it and see what games you have on "Ready to Install" and then copies those ones back to the main HDD and delete the rest.

Yes you can remove any accounts in the settings on the console, without going into the actual accounts. It shouldn't have any bearing on games or download speeds or anything else though, but if you just rather they not be there since you won't be using
that account for any reason, then yes you can remove them no problem.

Note sure if this will make much of an improvement to your download speed but you can follow the process here to remove those accounts:

https://support.xbox.com/en-GB/my-account/manage-gamertag-and-profile/add-remove-account-xbox-one

1. Press the Xbox button to open the guide.
2. Select System > Settings > Account > Remove accounts.
3. Select the account that you want to remove, and then select Remove to confirm.
4. When you're finished, select Close.

Dont care about download speed just trying to see were the games I can download and actually play are but it does help lol