mkraft asked:
<<Do brokerage fees for transactions in an IRA account *have* to be paid from the IRA assets?>>

Yes!

One [kind of] exception: If you have an annual accont maintenance fee, you can choose to pay that with funds from outside the IRA.

A technique that I have used is to make a small contribution for this tax year to cover a purchase that I want to make. Typically I [unFoolishly} make my IRA contributions near tax time for the preceding year. This was the norm when I was on the "borderline" in AGI for a deductible IRA, and I wanted to see where my income was before I committed the funds.