Suppose that the Magyar tribes manage to defeat the Pechenegs, and remain settled in Moldavia and southern Ukraine. Can the Magyars survive intact in this area, or will later invasions (Cumans, frex) disperse their population and disrupt any state-formation?
Regardless of what happens on the Pontic steppe, who grabs the Pannonian plain from the disintegrating Avars? The Croats, Frankish Empire, and Bulgarians all seem to have made some incursions before the Magyar tribes moved in, and IIRC, the Franks tried to solicit local slavic support against the Avars and Bulgarian empire.
Speaking of the Bulgarians, would they manage to keep Wallachia? They'd seem to have the resources with it to be much more dangerous to Constantinople, at least. Perhaps this brings the Magyars and Byzantines together, facilitating the former's conversion?