I think if we encounter any aliens it is probably because they have somehow managed to develop faster than light travel, which means we are fucked regardless of how many of us there are compared to them. God knows how far away our technology is from being able to develop anything like that, provided it is even possible. But who knows, maybe the aliens don't even understand the concept of violence.
In any case, there is too many variables to make any insightful statements about it. It is very easy to project aliens always as some slightly different version of humans, keeps it manageable to our brains I guess. Evolution is a funky thing though. Who knows, maybe some other race consists of giant hyper intelligent godzillas who reproduce once every 200 years who manage to keep a population of 20 going.
I highly doubt each of those hypotheses. Why ? Violence in nature is only the manipulation of basic physics to harm other things, in order to eat or to avert some perceived danger. A life form even sligthly similar to us (aka based on carbon/silicon chains) would necessarily learn violence in the process of developping tools, and much more probably way faster than that, as a prey. Maybe not use violence as much as we do, but certainly know it. Also, to develop our brains and agility we already needed millions of years. And that is with reproductive cycles that were relatively short. Species with super slow reproductive cycles evolve much much slower. Although now that I think of it, maybe that is the future of humans (I'm not an evolution expert and I have no idea). Other intelligent species could be very weird, no doubt (think of an animal with an amazing ability then add it to an intelligent species), but evolution and intelligence are quite resricting actually.
Now, if you think of "intelligent beings" outside of the scope of biologic things, you can let your imagination go wild, even though I don't know any lifeless structure complicated enough to do things our brains can do, except maybe the entire universe (are we in a calculator ?).