As far as puffing and strutting, No they don't need a girl friend. But they need something to threaten there dominace or strange noise. Being your only one he most like does have anything to dominate.
From the picture his snood is drawen up so he's pretty relaxed and easy going at the moment. Normally the snood will extend first before they strut.
When you just have males, or mixed males and females they will also do it. As they do have a pecking order they have to establish and mantain.
The bump may not be anything to worry about, he looks old enough that it should not get any worse. You do need to keep an eye on it is case it gets bigger, that might indicate that it is something foreign and infected.
Tom