Got some spare time to myself today and notice people have some questions about Danny.
@The Smashor
Yes, Danny can possess someone who is already possessed. He showed this in episode 3 of season 1 "What you Want". Tucker got ghost powers and took possession of someone then Danny took possession of the same person. Both trying to keep control but it was switching back and fourth.
@Smashtwing
1. Danny's Non-Physical Interaction is the same as all ghosts, they can harm intangible beings and the soul.
2. It's unknown to most people but Danny is still 8-A in his human form. However they did attempt to say otherwise in season 2 episode "Micro Management" where it made Danny and Tucker non athletic and weak compared to Sam. However this is false because throughout the entire series, Tucker repeatedly keeps up with Sam and has better feats than she does.
Danny is also comparable to Tucker and has even dodge Vlaire's lasers while in human form. Sam and Tucker have both taken Ghost Rays from a serious Danny Phantom, Tucker actually took two. Danny is obviously comparable to them and he survived being slapped to the side (In human form) by the
Lunch Lady Ghost who is able to fight him in his ghost form.
Vlad Plasmius who is half ghost like Danny also has feats. While in human form, he survived a Ghost Ray from Danny Phantom, he also took a Ghost Ray from human Danny that literally sent him several stories high and slamming into a billboard and he had a smile on his face.
So no, Danny's statistics don't drop to human level when in human form. He has feats of being comparable to other 8-A characters and scales to them. The only actual thing Danny gains from "Going Ghost" is ghost physiology. This is just unknown to most people, hopefully that answer is what you were looking.
Anyway, I'll leave you guys to it, got things to do. If you have other questions I don't know when I'll be able to answer since I busy for the 3 months. Luckily I just was chilling for a moment and saw y'all had some questions.