A typical Delphix Engine will handle multiple production Snapsyncs. Of course, this is workload specific!!
You can then use the simpler replication topology. That would be the preferred approach.
One reason to consider the more complex model would be if the source change rates were very high. You might then see CPU resource constraint on that first engine.
But that's unlikely. Many customers run 3+ dSources against a single engine; only about 1% of sources have very high change rates and would need their own engine. You should try bringing on each source and monitoring the CPU in performance analytics screen after it has fully loaded and goes into incremental Snapsync mode. You'll see the CPU increase as Snapsync compresses new blocks. Stagger your snapsync times to avoid large spikes.
It's very likely that the less complicated model (Hub and Spoke) will work for you.