What a great set of directional reflections on a question among the deepest of natural philosophy!
I strongly believe in the reality of numbers, including imaginary and complex numbers, and of mathematics as a whole. I believe the human mind approximates these things rather than inventing them. Here I will try to score 2 points against what I believe.
The counting of objects before and after arithmètic operations are performed on them, though often offered as evidence for integers, is more likely in practice to involve almost integers due to irregularities of replication in the purportedly plural objects being counted.
In their discovery and exploration of circular and n-spherical proportions, aliens — and indeed alternate humans — might well focus on a value other than π. They might prefer what some people denote by the Greek letter τ = 6.283185…, or the 2iπ common factor in the periodic incrementation of complex logarithms.
Did I score 2 points in favor of the Fictionalist position? Slightly less than 2, maybe, or slightly more? Closer to 3? Precisely e points, perhaps?
If so, my rejoinder to my total score and any point within it is this — the fiction involved is still a conceptual approximation to something real.