I'm new to Galciv3 and I was wondering if it would be possible to mod a race based on the following popular SciFi tropes: Zerg, Borg, Xenomorph, the Flood, etc. 

I'm asking because I'd like to play with such an original faction, but I think that wasn't included in the game nor modded by the community yet. 

The tropes of this faction should include: 

http://tvtropes.org/pmwiki/pmwiki.php/Main/AlienKudzu

One of the possible side-effects of an Alien Invasion.

 

In essence, Alien Kudzu is a plant-like, fungus-like, or otherwise predominantly sessile alien lifeform that infests a planet's environment and begins reproducing itself rapidly.

http://tvtropes.org/pmwiki/pmwiki.php/Main/HiveMind

In Sci-Fi or Fantasy series, the connection may actually be a true shared mind, either with each member contributing to the whole, or the separate bodies being puppets which some central mind controls remotely.

http://tvtropes.org/pmwiki/pmwiki.php/Main/HordeOfAlienLocusts

Because the only purpose they have in life, the be-all and end-all of their existence, is their insatiable hunger, the conversion of all organic matter in the universe into more of them. They don't do diplomacy, because you don't bargain with lunch.

http://tvtropes.org/pmwiki/pmwiki.php/Main/OrganicTechnology

Cars, planes, phones, computers, buildings,space ships,weapons (including artillery and war vehicles)and everything else required for a properSci-Fistory will be provided in the form of something that is warm, moist, skooshy and drips goo everywhere. Often, this will go so far as to include a convenient thought-based interface.Manipulation of organic mattermay be part of the technology as a whole, or even what enabled the tech in the first place. Advancednanotechnologywill often be depicted in a similar fashion

That said, this race wouldn't have to be evil. It could just be some ancient autonomous machines capable of learning, moved by the primitive directive to go forward and terraform the entire galaxy for a truly ancient and utterly alien species that doesn't even exist anymore. It's awkward pursuit at civilization and diplomacy would be nothing more than it's attempt at mimicking and mirroring what it sees as a pattern of succesful strategies in a galaxy teeming with other thriving alien civilizations. 

So, can GalCiv 3 mod a faction like this? Like an organic-themed pendant to the Synthetic race? How original and unique could it be allowed to become?

I modded quite a bit with GalCiv 2 back in the days, but havent even touched Galciv 3 yet, since the game doesn't seem to be quite finished.