With the planer off, I lowered the cutter assembly just low enough that the
infeed roller exerted just a little bit of drag on the board as I manually
pushed it in. I ensured that the board was not tilted upward as I pushed it
through.

When I continued to push it through, it stopped when it reached the outfeed
roller. I had to raise the assembly just under 1/32" to allow the board to
go under the outfeed roller.

Is the outfeed roller supposed to be lower than the infeed roller since the
assumption is that the board is thinner once the blades have removed some
wood?

I verified that the bed is coplaner with both the infeed and outfeed tables.
I then inserted my 6' planer sled and verified that it was flat and level.
The inserted board did the same thing: stopped when it hit the outfeed roller.