I hope this finds you well and thanks so much for your patience while I was working to update the extension with my team. We were actually able to push through an update yesterday afternoon which set the default lifecycle stage to lead in the sidebar. If you take a look now, that should be in place. If it has not updated yet, I would recommend uninstalling and re-installing the sales extension so an updated version and be pushed through.
Again, I want to say that I sincerely appreciate that you took the time to reach out to us and help us iron this out. HubSpot really values constructive feedback with real use-case backing to help push it along. So, thank you!"