I've read all about digging 7 or 8 inches deep
for laying all of the base materials. I had also briefly considered a
"raised-bed garden" (or whatever the proper term is) in this spot.

So... my idea was to combine the two concepts (thus a slightly raised
patio)... "frame" the area for the patio on top of the existing
ground, then use a little extra top soil to fill in some "divots" or
depressions, ensure the slope is good again, then lay down the base
materials, then the stone...

What is important is the solidity of the base. Topsoil is generally not as
hard and compactable as clay. The failure may not come for a few years, but
if the ground moves, heaves, whatever, you will end up with cracks or worse.
If need be, pay someone to do the digging, but do the job right. Fixing it
three years later will be much more labor, much more.