I'm still 7 years off FIRE, but my current, and intended portfolio is 100% stocks, but I don't intend to use the 4% rule. Instead, I intend to retire on the maximum of dividend yield and 4%. In general, dividends are nowhere near as volatile as stock prices. Usually, when stocks boom, dividends only slightly increase, and dividend yields get smaller and smaller. Then, when there's a crash, usually dividends fall a bit, but then recover fairly quickly. With my stocks in 2008, it was about a 20% drop, but they'd recovered after 3 years.
Lastly, I should say, I live in Australia, which is happy, happy dividend land. My stocks are currently yielding almost 5%, so I could live on 4 - and still build my investments.