Which of the following would beat Ibeabuchi at his best?

Ike wasn't short, or unskilled at all. He had a decent jab, and decent accuracy. Good enough speed to track down and take out a prime Chirs Byrd, or go toe to toe and outwork Tua. An all time could have been if you will.

I'd pick Ike to win 5 pretty easy. I'd guess 6 or 7 of the 8 listed names based on how they match up.

Ike's main flaw might never have been shown in the ring. He had some mental issues and when matched vs a more polished / versatile puncher, or top counter-puncher, he could have some issues.

In the Tua fight, his corner told Ike midway through the match " Don't Quit ". Ike didn't, but the fact they said it and knew him best indicates something they were worried about.