I found this relatively new sprite creation program called Aseprite 0.95, when I attempt to create a new sprite, I am presented with this screen:

When I hover over Indexed with ___ colors, a tooltip says "using a palette of 256 colors (8 bits per pixel)"
When I hover over RGB Color the tooltip says "RGBA Color Mode (32 bits per pixel)"
When I hover over Grayscale, the tooltip says "Value and Alpha (16 bits per pixel)"
Using that information is Aseprite suitable for creating genesis/megadrive graphics, and if so, what would I choose if I wanted to create a character similar to the images below?


Sorry if I seem rather noobish, it's because I've never done these kind of graphics or game programming at all before, so I've decided to begin on older consoles to mimic the style of some of my favorite games.