Should I wait until the wort is cooled to pitch the yeast or pitch at the higher temp and let it work as it cools down.
It can be done either way, but the cooling time should be less than your yeasts' lag time, i.e., the wort should be at your desired ferm temp before the growth phase begins, because that's when all the flavor-active stuff (both good and bad) get made. If you're seeing signs of fermentation after 10 hrs but the wort is still at 64 because the brewjacket cools so slowly, you may get a more estery lager.
Should I aerate the wort after it has cooled down to pitching temp?
Aeration should be done immediately before or immediately after pitching. You want to the yeast to mop it up quickly to make them happy but also so that the O2 doesn't have a lot of time to react elsewhere. Also, the O2 will off-gas a bit, so if you aerate but then wait 24 hrs to pitch, the yeast will have less O2 than you intend.