Reality itself is beyond us. All that we have at our disposal are our perceptions, which is what we are modeling when we "do math". Mathematics is not universal, it's a language that we use to communicate what we perceive to other humans.
It's speculative, whether an alien species, with a perceptual and cognitive system evolved entirely elsewhere under other pressures, would have an understanding that intersects with our subset of reality. I personally think it's unlikely. What that would mean is that we wouldn't be able to communicate, never mind trade technology and mathematical ideas.
I mean, maybe, but this is conveniently unprovable, much like the flying spaghetti monster, since you are saying we could not communicate because our slices of reality don't intersect. I disagree and think that most likely we would live in a reality that was largely the same, but I guess we'll never know!
Perhaps. I was responding to the assertion that Mathematics exist independently of biology or perception of reality which is at least as unprovable