Papapaint
Just your average kind of Luigi.
An important note on fast-falling aerials:I actually think that the N-air is a better than you say it is because it has next to no landing lag after a fast fall. You can also N-air them after an Up-tilt for some added damage as well as attack people on the platform above you and I think that you could get an N-air in after a down throw on most characters.
I'd also like to say that the easiest method of spiking people for me is running off of the stage, using your second jump and using the D-air while rising up. It's probably the safest way to spike as well.
Just trying to give my input. Thanks for taking the time to write this, it looks like it will be a lot of help.
I discovered when testing these on slo-mo that any fast fall aerial will AUTOMATICALLY CAUSE YOUR CHARACTER TO CROUCH UPON HITTING THE GROUND. This is not a significant amount of lag per se, but enough that I would not recommend attempting to use it in a competitive situation.