The OP focuses on the initial conditions. What precedes the initial inflation? What is at t=0? The standard model starts with zero space, maximum crunch. But that implies that the singularity "exists" in a timeless state. Spacetime necessarily arises contemporaneously with the expansion. But back at t-zero is the crunched singularity, stuck in timelessness, analogous to the frozen images of matter entering a black hole. The best analogy I could get taking your proton tennis ball would be to start with a photon, stranded in time, and then start it racing around in random spherical trajectories of ever increasing radius, emitting light in the process. The light is ever changing, but the photon itself is stranded at t=0. This would more or less illustrate my remarks about the crunched singularity co"exist"ing with the time-tagged inflating and expanding products of its "emission".