Skip the CPDs, I have some in a nano tank, but they are indeed shy and would just hide in a busy large tank. You'll hardly ever see them.
Maybe instead of guppies, get an all-male group of Endlers, as they have a bit less bioload, freeing you up for small cories. I have both pygmaus and hasbrosus. Pygmaus are cute, but will spend roughly half the time on the bottom and half the time midwater. The hasbrosus though are just like tiny versions of the larger cories, but you could have almost a dozen if you skip the CPDs and swap for endlers. You could also instead do 5 or 6 pandas, but cories are most fun in bigger groups, so hasbrosus would be my 1st choice here.
Agree with the cautions mentioned about the gouramis. Most of your fish here are really small anyway, so maybe a group of croaking (aka sparkling) gouramis would be better than getting a few the larger ones. They are beautiful once settled into a planted tank, and won't get big enough to threaten anyone.
I also suggest slightly increasing the headcount of tetras. More in the group will result in better schooling behavior and a much more impactful display in your tank.