By “wildlife” does that include aliens? I know this sounds crazy. I never gave any of this much thought at all until this whole Venus thing came up.
Well, perhaps we can think of it in three different levels.
Microorganisms - In Biblical terms, this falls under the category of nature, not creature. Though we can rightly understand them as living in scientific terms, they are not classed as such in the Biblical framework. Bread is inanimate, even though it may contain yeast, which are living microorganisms. To put this a bit more forcibly, it's not murder to eat bread, because we recognise it as a thing, not a being.
Developed creatures - In Biblical terms, this would essentially be no different from fish, birds, and animals. If we were to find these creatures in space, they would essentially be wildlife, only extraterrestrial - outside our atmosphere. I think it's a fair assessment to say that space is simply nature. Nature doesn't stop where our atmosphere ends, but extends into the universe. So what we would call wildlife on earth would also extend to similar beings in space, if they exist.
Though I think this is highly unlikely, let's for the sake of the argument say that we found a 100 different animal-like creatures in space with varying levels of intelligence, ranging from insects to cats to dolphins. I think at that point, although we would probably retain the distinction between earthly life and extraterrestrial or alien life, they would all fall into the category of wildlife. Though many, if not most secular thinkers, would probably go a step further and include humans in this category - as they already do in thinking of man as a kind of animal. To use a different example - a rock on earth is called a rock, and a rock on Mars is also called a rock. We don't have to make a distinction by necessity. So aliens could just be thought of as animals.
Intelligent beings - If we take this to mean something as advanced as or more advanced than human beings, this would present a different problem. Then it would be a question of whether God created some animals more intelligent than humans, and what that means for morality, or if He created different beings with souls. In either case, I think this is a next to impossible scenario, so it shouldn't be something we need to speculate or worry about.
Whatever beings we may find in space, God has promised to redeem and renew the entire cosmos, which includes everything from the tiniest cell to the largest nebulae, so while it may cause us confusion and division, it has no bearing on God's Word, which is true and eternal. God's Word and His love endures forever! God be praised!