I would for sure take a good look at the default properties and what you might need to set up because you start going too far outside what might already come with the system. Just to save the headaches of duplicates or not leveraging the value of some of the default HubSpot tools. It is so easy to create new properties you should be able to get things moved in no time.
Sadly I don’t think ACT has a nice integration like Salesforce does which is almost a few click migration of the majority of your database (this includes fields which caused me to have some initial duplication to clean up).