I would say no. If you cut a hole in the asphalt you could drive it through. It does not need to be very large of a hole maybe 2x2 or 3x3 inch. My biggest concern is what's under the asphalt, how much gravel?, might be difficult to drive it nto the ground.
It will not support the weight of a gate. I used mine as base for a Rubbermaid mailbox that mounts to a three foot 4x4 wood. I can easily push the mailbox over, if I wanted to.
Yeh drill and chisel it out. Next time trim the 4x4 so you can easily remove it.
Yes it will work if post is securely attached to spike
I have no experience with that high of winds but do get 20 to 30 and they do just fine
Personally, I wouldn't trust these spikes to hold posts on their own. I always use them in addition to concrete. I dig the hole for the concrete foundation. I attach the E-Z Spike to the bottom of the post. I drive the post and spike into the bottom of the hole with a sledge hammer. Then, I fill the hole with concrete. The spike keeps the post upright while the concrete cures. I have built several fences this way (up to 7' tall). And, it has worked great.
Not only would this violate building codes .. .the reason the codes exist is for safety. If you violate this and the deck fails and there is an injury, your insurance may not cover this (actually it SHOULD NOT COVER THIS) and you could be criminally liable. Medical cost, court costs, yada yada da. Also: (in most any area) you need a building permit before you build a deck (which would not allow this). Once the deck is complete then the deck is signed off (essentially a certificate of occupancy). If you lack that, you can not sell the property.