The earliest evolutionary organism would have to be a single molecule (probably RNA) able to reproduce itself with potential mistakes in a very specific environment (probably rich in organic molecules) that happened to be common enough at the time this organism appeared.

Anything with multiple molecules would most likely be too complex to appear first without previous evolution to learn to make those molecules and a container.

Because we don't know what was this early environment (there's some hypothesis, but no clear answer), we can't test what was the smallest RNA possible.