Shinedrop is perfectly safe if done perfectly. You will be shielding one frame, and shining (therefore, invincible) the next frame. The problem is shine has ****ty range. The same goes for grounded shine OoS, but there are 5 frames of jumpsquat before the shine comes out. Falco's grab range is way better than the range on the front of shine, and it's only 1 frame slower, so that is a much safer option if you're looking to counterattack.
Shield drop nair is really hard to get out ASAP, so idk how fast I could do that. Bair hits frame 4 so it's faster than grounded shine, and more important it has way better range. Even if you trade shield drop aerials it's usually worth it because not only did you get out of pressure, but you are treated as being below the platform so you will be sent towards the ground while they will be higher up in KB for about the same amount of time. Uair comes out pretty slow, and I have a feeling the second hit will almost always miss. The first hit being weak also makes trading not in your favor. Fair I just treat the same as bair. A little slower, but the hitbox hits pretty high so it's not hard to connect with, and its low KB is great for followups if you can hit with it clean. Dair is actually really cool. I want to experiment with it more to figure out how exactly I can followup shield drop dair hits. They have to be pretty deep in your shield though, so I usually just take the free shinedrop when that happens.
One of the safest options is actually just empty shield drop. Especially when you are playing opponents who are aware of your ability to shield drop and will play around it by spacing away from your shield or placing (or faking) hits on your shield in such a way that they can punish you under the platform. Just dropping through without an attack leaves you free to double jump and bair/dair them on reaction if they do something unsafe after you drop through, and if they don't do anything like that then you can just go right into controlling the bottom level of the stage by moving instead of throwing out a useless attack.
