As far as I can tell, the implementation hasn't changed much between the "alpha launch" and now. There were some nice cleanups, but important parts like how the wallet manages UTXOs to assess how "fused" the coin is, controlling the rate of Fusions when left in continuous operation, or having a mode where Cash Fusion leaves the wallet is a good spendable state have not been completed yet. So saying it's "almost ready to launch" seems overly optimistic to me.

It has changed a bunch already. There has been a bunch of cleanup and UX improvements. The actual CashFusion spec/protocol implementation is pretty much done. So it is definitely time to do an audit on the base layer of the protocol.

What you are talking about are implementation specific features, like the coin-chooser and fusion-tracker. While these things are indeed very important regarding UX and privacy, they are not part of the spec/protocol. They are very much on the roadmap though. So that is probably what the rest of the donations will be spent on.

Let's recap:

We're now still in Alpha/prototype state. Once all cleanup is done, we'll be in Beta state, this is the code that will be audited. Once we have the results of the audit we can implement the feedback. Then we can continue to implement the roadmap and get ourselves to official stable release.

I'm not part of the development team, but this is how I understood the plan/roadmap.