Just think the work rate of Ibeabuchi would be to much for Joshua in the long run. Joshua’s size and power could trouble everyone, but I have yet to see him fight at a high pace for several rounds. He would have to take a breather at some point, and be there for the taking. Joshua is still a little green though, so he may very well up his game in the coming years. Wilder always has the chance of landing his right hand flush, but he is a very slow starter. He would see Sun, Moon and Stars before even getting out of second gear imo. Just to clarify, I don’t consider Ibeabuchi some ATG killer that would just blast through everyone post 90’s. He would have a hard time against either Klitschko brother, especially Vitali.
That was just to point out Joshua isn't this h2h unbeatable monster many Brits seem to think. Ibeabuchi held his own against top tier talent in a relatively strong era. Wlad at 41 gave Joshua massive issues. Hard to see a fighter of Ike's calibre in his prime not doing the same.
He’d be a tough fight for anyone Ike was the real deal he was strong, a good puncher, could take a punch, and had good stamina. I remember reading he was always a little crazy but after the Tua fight he started getting headaches and I believe hearing voices.