Hound doesn't have to mean sighthound, in fact usually it more often refers to scenthound, which is present in dogs like filas and cuban bloodhounds and presas (although less evident in the presas phenotype, it is there). Great danes I think have both sighthound and scenthound. 

That said scenthound is no doubt present in a lot of ambulls as well, when I said ambulls I was thinking of compact real bulldogs, which most ambulls today aren't, and indeed are more veantre in nature. I think the line between veantre and boucheries is pretty blurred because I think essentially both are catch dogs. In fact I think all 3 are essentially catch dogs with slight variation in their area of expertise and there is blurring between all 3 of them. Hence them all being under an alaunt umbrella.

Gentil is a fast running catch dog

Boucheries a compact agile catch dog

Veantre a heavy hanging catch dog

3 functions and types which persist to this day in any mongrel boardog population. 

To me both the bully kutta and modern great dane blur the line between veantre and gentil, the ambull and presa blur the line between boucheries and veantre, a bull arab or bull grey blurs the line between boucheries and gentil, etc etc. The 3 types are kind of points on a spectrum where the members of the gripping dog family land somewhere within, being real animals not bred in such a black and white way to be clearly one or the other. 

Gentil, veantre and Boucheries shouldn't be seen as distinct breeds, but descriptions of roles and functions and the general type that aligns with them. 

Anyway, the bigger point I think, is that all of the above are "hounds", as in hunting dogs, and specifically dogs used to catch quarry. "Alaunt" in medieval europe was used to describe the variety of catch dogs. 

The confusion I think is that they are called alaunts and supposed to be based on the alani dogs, when the alani dogs were more than that. Primitive all purpose dogs developed by a tribal people to guard them and their flocks and perhaps hunt as well. 

Alaunts were something else from a different era, it's just a name given to mongrel catch dogs in medieval europe.