Ship to Shore has coming soon placeholders for Gradius 2 and 3 on their store. They made an announcement on Facebook but didn't mention when these will be available.
https://www.shiptoshoremedia.com/store/albums/gradius-ii
https://www.shiptoshoremedia.com/store/albums/gradius-iii
https://www.shiptoshoremedia.com/store/albums/gradius-ii
https://www.shiptoshoremedia.com/store/albums/gradius-iii