I posted this solution yesterday in another forum.
For anyone still have trouble finding a way to delete autofill addresses on Android, this is what worked for me.
None of the addresses that showed up for me when I typed a letter in the To: field on my Android appeared in ANY Contact list on either my phone or in Other Contacts when I signed into Gmail on my computer. I also had no way once the address appeared in the To: field to press and delete the address. The problem has nothing at all to do with the keyboard you are using on your Android. If you've made sure that the addresses don't appear in any group on your phone or computer, then try this...(phone instructions are using Lollipop on Samsung Galaxy S5):
On the computer, sign into your Goggle account. Open Gmail. Click the Gear icon to get to Settings, General Tab, scroll down to "Create contacts for auto-complete", Check "I'll add contacts myself". Apply. Do this for any/all Gmail accounts that you have that download/sync to your phone. Doing this makes sure that any addresses you reply to in the future are not 'saved' as auto fill possibilities.
Now remove your Gmail account(s) from your phone. Swipe down from top of phone to access Settings, Accounts, Google, Click on the account to remove (the one or ones you have the autofill addresses you want to get rid of), Click Menu (three vertical dots), Remove Account.
Once account is removed, click the Gmail icon, Menu (three vertical lines), Settings, Add account, Check Google, Enter email address, Enter Password. Account will be re-added. Click the Gmail icon again and compose a new message. Enter a letter into the To: field and the nuisance addresses should be gone.
For anyone still have trouble finding a way to delete autofill addresses on Android, this is what worked for me.
None of the addresses that showed up for me when I typed a letter in the To: field on my Android appeared in ANY Contact list on either my phone or in Other Contacts when I signed into Gmail on my computer. I also had no way once the address appeared in the To: field to press and delete the address. The problem has nothing at all to do with the keyboard you are using on your Android. If you've made sure that the addresses don't appear in any group on your phone or computer, then try this...(phone instructions are using Lollipop on Samsung Galaxy S5):
On the computer, sign into your Goggle account. Open Gmail. Click the Gear icon to get to Settings, General Tab, scroll down to "Create contacts for auto-complete", Check "I'll add contacts myself". Apply. Do this for any/all Gmail accounts that you have that download/sync to your phone. Doing this makes sure that any addresses you reply to in the future are not 'saved' as auto fill possibilities.
Now remove your Gmail account(s) from your phone. Swipe down from top of phone to access Settings, Accounts, Google, Click on the account to remove (the one or ones you have the autofill addresses you want to get rid of), Click Menu (three vertical dots), Remove Account.
Once account is removed, click the Gmail icon, Menu (three vertical lines), Settings, Add account, Check Google, Enter email address, Enter Password. Account will be re-added. Click the Gmail icon again and compose a new message. Enter a letter into the To: field and the nuisance addresses should be gone.