4. You could set a secret question and its answer for password reset.
Once you set the secret question option you cannot disable it, so before setting it, learn its pros and cons. For more details, see Tips below and
Change password and email / Forgot password.
Actually you can.
Profile > Account Related Settings >
Remove anything you have on the Secret Question field
Remove anything you have on the Answer field
Then update the profile. I have done it before when I realized that account recovery using secret question feature will lock your account. So, there are no use of it, in-fact extra risky.
Oops! LoyeceV already have it

An addition: use a password manager! I have hundreds of different passwords, and there's no way to remember them all. They're all safely encrypted inside my password manager, so I only have to remember the master password (and make backups).
I have a text file with all the passwords I use for my web accounts. Has an eccrypted backup file as well.
- For password, do not use dictionary words, your birth date, pets name, phone number, ....
https://passwordsgenerator.net is very helpful.
Tips for 4: Secret question
- There are several important things to know about the secret question feature.
1) Once you set the secret question you cannot disable the feature.
2) There is no email verification process, so most likely the secret question option increases the risk of your account being hacked or locked.
3) If password reset via secret question is used, your account will be locked, and you need to follow Unlock your account process. If the account is under your control, this feature is a drawback
I hope you are working on it since information about secret questions are wrong.
3) Password reset via secret question.
Don't, account will be locked.
Tips for 3) "Secret question":
You really need to update this section.
3) you login after a long period of inactivity.
I doubt it if it's not related to 2015 hack.
Anyway read the whole post and you just need to fix everything that is related to secret question other than that well done!