Frustrated from not finding any simple how-to-shrink-vmdk-and-reclaim-hidden-space guide?
I guess you've never heard of the KISS principle? It's an acronym for "Keep It Simple, Stupid" and your directions are anything but keep it simple however you nailed the last part! There are also some things wrong and unnecessary however since the real solution is so simple I'm not going to waste my time pointing out the flaws in what you've written.
A much easier way to properly perform a P2V is simply to use the free VMware vCenter Converter Standalone downloaded and installed directly onto the Windows PC and create a Virtual Machine directly from Windows to an external drive setting appropriate parameters as one walks through the Wizard. You'll end up with a right-sized proper type virtual hard disk from the word go and then it's already on the external drive if there is not adequate free space on the Mac. Or if there is, you can then simply drag and drop the Virtual Machine from the external drive to the internal drive and you're done.
In your defense, the Migrate your PC... function in VMware Fusion is a half baked implementation of VMware vCenter Converter Standalone and is often problematic for some uses to get a connection between the source and destination to even perform the migration and doesn't offer all of the abilities to configure the resultant Virtual Machine like VMware vCenter Converter Standalone does. So IMO if one needs/wants to P2V a Windows system to a Mac (or other platform) using VMware vCenter Converter Standalone writing to an external drive is the better way to go! 