Hi, welcome to the team
I personally don't think panspermia is very interesting because life has to evolve somewhere, even if, after that, it is spread around by meteorites.
If you'd like to make a prototype of a 0th stage for the beginning of life then that's cool, it would be interesting to see. The general philosophy is people are free to work on what they are interested in.
In order for it to be in the game it needs to be scientifically realistic (which is a bit of a challenge for abiogenesis as there is not yet a widely accepted theory on how it works, however something plausible might be enough) and it needs to be fun for the player to interact with (what do they control and what is fun about playing around with it?). So long as it satisfies both of those then it'll make sense with the other stages!