Re: "Can't reset iPad mini password, lost email access"
If you have another Apple device (or computer), try logging in on that to see whether the iPad mini is still listed there in your Apple Account. If so, the iPad mini may also log-in with the same details listed in the Apple Account .
If iPad mini is not listed, you may want to try adding the iPad mini as a new device by signing in to your Apple Account on the iPad mini with the current Apple Account details. You can get a verification code to enter on it, from the other device (or computer).
See how to:.Get a verification code and sign in with two-factor authentication - Apple Support
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If all else fails: Apple provides an account recovery process ... it may take quite some time.
"The account recovery process helps you reset your password and regain access to your account. If you can’t remember your Apple Account password, make sure you’ve tried everything else before starting account recovery – for example, using a different device that’s already signed in to change your password."
See: How to use account recovery when you can’t reset your Apple Account password - Apple Support