Oh, another case like Alvida. I like this supposition

Who are Spandam Shoes, Lady Crocodile, Dr. Blackbeard? Why is there Norland in this poll? I vote for Sir Crocodile. He is an awesome character. I think we'll know his past soon. He has many great characteristics especially his style. He might have a changing past which fits many Straw Hat crewmembers. And his dream is to become Pirate King, a great dream

Up to now Brook hasn't shown his strength. I still wonder about his former 30 millions berries bounty in his previous life

1 hit isn't good. And I don't think Kuro would be interested in returning to Syrup Village. They may meet again at another place in East Blue

He is now imprisoned. If he is imprisoned in Fishman Island, we shall meet him again

I think:
Brook vs Unamed Guy
Nami vs Lafitte

I love original "We Are"

An interesting supposition. Morgan becomes Kuro's first mate. They becomes stronger and arrive in Grand Line to revenge Luffy. I used to think of an interesting but impossible idea: The last bosses of Straw Hat crew who joined in when they were in East Blue are the original bosses in East Blue:
Luffy vs Higuma, Buggy, Alvida
Zoro vs Morgan
Nami vs Arlong
Usopp vs Kuro
Sanji vs Gin
Think of Krieg, he may be suitable for a battle against Franky
It's only a crazy supposition, so don't laugh at me ^^

Higuma is the first villain in One Piece. The supposition that he isn't dead and will return is quite interesting but impossible. Higuma is really dead. The details from manga, anime and One Piece Wiki prove that

Hatchan has said that all of Arlong Pirates crew are imprisoned and he is the only free guy