"I looked online and could not find anything that says I cannot
power other receptacles from the GFCI or that I have to use pigtails
from the GFCI to the wires that go to the other receptacles."

I stand corrected, that is a local thing. On regular outlets it is bad practice, but on a GFCI outlet, that neutral coming off the protected terminal is not going to be shared anyway, it would trip as soon as the other thing turns on.

I would only do it on a new circuit, you KNOW how that is connected.