Any product designers have experience being interviewed by the lead engineer? (Only, no one else) I’ve never had this happen and was curious on some tips to consider!

Yes, a few times. In my experience, these are not very difficult interviews, nor do they ask anything technical. It's usually moreso a way to see if you would enjoy working together. Chances are you will be sending your work to the eng lead and they will delegate implementation

I would be prepared to talk about your design process and how you interface with engineers. They might ask about collaboration style, how you like to receive feedback, etc. One Sr. Eng. I interviewed with directly asked me about a specific project they had seen on my website.

Thanks Josh! This was super helpful!

Thank you!