I think that the solution you suggest resolves Zeno's paradox! It is very similar to Whitehead's argument presented in Part I of Process and Reality and presupposed in the Theory of Extension in Part IV. If you recall from Aims of Education he holds that a line is a "moving point" while a "plane is a moving line." Along with von Neumann's work on mathematical rings, Whitehead relies on a continuous, point-free projective geometry of non-finite dimension. Whitehead's "extensa" or extensive structures are logically and metaphysically prior to time and space as topological relational systems (mathematically speaking, they may be seen as spatial, but this pertains to "spatial reasoning"). This allows for the openness in which "universal relativity" (not to be confused with Einstein's as only a single application) and "atomicity" are compatible. He writes:
The creatures are atomic [i.e., undivided]. In the present cosmic epoch there is a creation of continuity. Perhaps such creation is an ultimate metaphysical truth holding of all cosmic epochs, but this does not seem to be a necessary conclusion. The more likely opinion is that extensive continuity is a special condition arising from the society of creatures which constitute our immediate epoch (PR, 35-6).
This compatibility allows for the "becoming of continuity" and not a "continuity of becoming" as is assumed in Zeno's paradox. Under the conditions of our epoch
The extensive continuity of the physical universe has usually been construed to mean that there is a continuity of becoming. But if we admit that ‘something becomes,’ [in the physical sense,] it is easy, by employing Zeno’s method, to prove that there can be no continuity of becoming. [Where we are speaking exclusively of the way that actual entities, considered physically rather than logically, divide the extensive continuum there is a becoming of continuity, but no continuity of becoming. [Under those assumptions, the actual occasions are the creatures which become, and [to that same extent, in the physical sense only] they constitute a continuously extensive world. In other words, [physically speaking,] extensiveness becomes, but ‘becoming’ is not itself extensive (PR, 35).
I think this is a definitive claim and is consistent with what you include with some slight variation. These distinctions may seem petty but they are crucial for the methodology of a post-Kantian speculative cosmology.