If they summon several of them it's likely the HKs actually fall in this arc
It can't be like Egghead or the arc actually ends badly with Elbaf getting invaded but I don't see Oda doing that.
If the HK fall this arc and the Strawhats are responsible for it. Go ahead and tattoo fraud on Dragon's forehead.
Let Papa Lee take it from here.
So Elbaf is the post timeskip Amazon Lily. The Holy Knights are the post timeskip equivalent to Momonga and the Marines, and the Marines left Amazon Lily after successfully convincing Hancock to join them.
So Oda’s own plagiarism logic at play, this means the Holy Knights will also leave Elbaf, only this time the WG will be unsuccessful in forcing Elbaf to join them, unlike Hancock where they did succeed.