Ideabuchi was a headcase and was ready to implode at anytime so it would have to be perfect timing to make this match up. For a short period Ibeabuchi would be a live threat to Lewis he had good power, good chin, good workrate, so Lewis would have to be on his A game. My issue is we never see Ibeabuchi take on a big skilled man who would be bigger than him with a longer reach so we're playing the guessing game in regards to how effective Ibeabuchi would be vs that type of style.
Lewis for me and I don't think it would be particularly close. Lewis could box and slug as needed, and I think he's better in either department than Ibeabuchi. Ike's problem is that he was kind of slow and tanklike, and didn't have much defence. That means that Lewis can try blast him out, and failing that has a very valid plan B of simply outboxing him with his much superior ranged skills. Ike has one plan, to plod forward taking them in the kisser and hope to wear Lewis out. I mean, I guess it's possible. What's probable however, is that Lewis cooks him like a christmas turkey.
It would have been interesting to see Ibeabuchi's rise, coming into the new millennium, and there's no telling where his career might have led, had it not been for his troubled personal life. But, as it stood in 1999, Lewis would most likely have mugged him.