I believe you're able to roll your 457 accounts into a traditional IRA. However by doing so, you lose the biggest benefit of the 457 plan compared to other retirement accounts: the ability to withdraw the money prior to age 59½ without paying a 10% early withdrawal penalty. If you already have enough in your taxable accounts to last you until then, you might not care so much about this, and would benefit from moving to a lower-fee account. It's definitely something to be aware of though!
Yup, that's all correct, so long as this is a
governmental 457b (OP, it's a 457b, not 457k).
The penalty free withdrawals from 457b's kick in once you leave your employer.
Hence, do not rollover your funds. Just withdraw from the 457b (or from your taxable, whatever floats your boat). This way you don't need to attempt the Roth pipeline (although the Roth pipeline is essentially useless to you anyway since you'd be 54 in April 2016 when you FIRE, and you'd be 59.5 in October 2021. You can withdraw from your traditional retirement accounts penalty free starting 1/1/2021 (it's the calendar year in which you turn 59.5, not when you literally turn 59.5). The Roth pipeline takes 5 years to prime. )