I know you said solved, but, as a possible non 3rd-party solution: I'm using Nova launcher too. I just saw in the "More Features" menu (above) that there's an option to download an S-Note widget, which I downloaded.
Then, when selecting an open space on a Nova page, I added the 5X1 version of the S-Note widget, and then resized it to only show the 2 leftmost icons (for "View" existing and "Create New"). So, it's not an actual Action Memo on the home screen, but it is a Samsung app with an icon to create a new action memo on my home screen.
HTH,
crp
Then, when selecting an open space on a Nova page, I added the 5X1 version of the S-Note widget, and then resized it to only show the 2 leftmost icons (for "View" existing and "Create New"). So, it's not an actual Action Memo on the home screen, but it is a Samsung app with an icon to create a new action memo on my home screen.
HTH,
crp