The risk of an early retiree having a low equity allocations is that inflation will probably hurt you badly in the long run.
However, there might be a reason to start at 30% equities as long as you let your equity allocation rise over time. Check out Kitces "equity glide path" work in this area. he is trying to address the risks in the first 15 years. As Clients Age, Stock Up on Stocks: Kitces
I see you are mentioned the Pfau approach. There are already quite a few threads discussing the rising equity glide path in this site.
I would never drop below 30% at the start however. Long-term portfolio survival doesn't do will with low equity exposure.
Personally I probably won't drop below 45% equities until I'm well into my 70s. I'm at about 53% now.