Title lacks hyphen, but that is not mistake, as POD is not about Das Haus Habsburg-Lothringen.
IOTL Emperor Frederick III seeks for wife with connections to Kingdom of Naples (IDK why, perhaps to strenghten his claim to Hungary?) and before he married Eleanor of Portugal (niece of Alfonso V of Aragon, who was also King of Naples) he also considered marriage with daughter of Alfonso's rival, Rene of Anjou (Yolande or Margaret), so if René is victorious (perhaps to more disastrous for Aragonese side Battle of Ponza) he is likely so stick to that original plan (perhaps Yolande is widowed early and marries HRE Frederick as second husband around 1450). Assume, that Nicholas dies like IOTL (yes, yes, I know-dense butterfly net required) that makes Holy Roman Empress his successor. Vaudemonts are screwed-they could still present their claim, but Lorraine is part of HRE and their rival would be Emperor himself. So in 1473 Lorraine is inherited by Habsburgs, what happens then? What would relations between Habsburg Lorraine and Burgundy look like? I guess Charles the Bold would not be mad enough to try to conquer it? Not that Habsburgs were invincible (Matthias Corvinus proved that they were not) but having both King of France and Holy Roman Emperor as enemies certainly would not be wise.
IOTL Emperor Frederick III seeks for wife with connections to Kingdom of Naples (IDK why, perhaps to strenghten his claim to Hungary?) and before he married Eleanor of Portugal (niece of Alfonso V of Aragon, who was also King of Naples) he also considered marriage with daughter of Alfonso's rival, Rene of Anjou (Yolande or Margaret), so if René is victorious (perhaps to more disastrous for Aragonese side Battle of Ponza) he is likely so stick to that original plan (perhaps Yolande is widowed early and marries HRE Frederick as second husband around 1450). Assume, that Nicholas dies like IOTL (yes, yes, I know-dense butterfly net required) that makes Holy Roman Empress his successor. Vaudemonts are screwed-they could still present their claim, but Lorraine is part of HRE and their rival would be Emperor himself. So in 1473 Lorraine is inherited by Habsburgs, what happens then? What would relations between Habsburg Lorraine and Burgundy look like? I guess Charles the Bold would not be mad enough to try to conquer it? Not that Habsburgs were invincible (Matthias Corvinus proved that they were not) but having both King of France and Holy Roman Emperor as enemies certainly would not be wise.