I thought about suggesting making ruins or buildings built by them and for them as natural objects, but then I thought that was maybe too much effort and they then would have to be scanable like anomalies, which would mean there would have to be descriptions and lore for those buildings, etc. And then there's the queston of how terraforming would affect the aliens. If they're evolved to live in regular, non-terraformed mars conditions, how would they react to terraforming, and at what point would they die out...
Maybe a bit too much. But thoughts I had. But it's your mod, and your decision what to make with it.

Not a bad idea

I think of those as native martians. For that reason, when they spawn, they should emerge from the ground, and live in the underground caves. That would be my suggestion. No ship drop-off animation when spawnning or pick up animation when despawning, but a coming out of the ground and burrying back down into the sands anims, and making them way more common underground in the explorable caves.

You might have an old copy installed or something?

There is a message at the game startup that notes this mod is not compatible. Is an update required or is this just a glitch?

The update works perfectly. I just went back in game and Bam , there was a little alien. They are adorable.

Updated

Are there certain prerequisites before these little aliens will appear? I have the mod installed and started a new game. I am playing a bit with no humans currently. Do I need to have human colonist to trigger these alien visitors? (I have been playing the new game for about 4 hours and have not spotted any . ) Thank you for sharing your mods with all of us.

@SkiRich Couldn't be Roger, he's not wearing a wig or women's underwear.

It's a mod on the workshop.

Could you please tell me how to enter the mod config option?

Looks like the character from American Dad.