Q: notes not showing in icloud

If the other notes were created on your iPad before you enabled iCloud syncing for Notes, then would not have been added to iCloud.  Open Notes on your iPad and tap Accounts on the top left (if you see it).  Then see if the other notes belong to the On My iPad account.  If they do, they were probably created before you turn on Notes syncing with iCloud.

You're welcome.  If you want your Gmail to go to your iCloud inbox you would need to set up email forwarding in your Gmail account settings to forward your incoming Gmail email to your iCloud email address.  iCloud doesn't do anything with your Gmail.

That's the bad news.  At the present time only way to do that is to open each one, then copy and paste the text into a new note created in the iCloud account.

You're welcome.