So if Theropod dinoaaurs are seen as being more or less the ancestors of modern birds. Then by all means, does it means Ceratopsians or Sauropods or even Hadrosaurids have a modern descendent? And it could it even be said that those families had something in common with birds?
We have to be very specific, and look at it this way:
All of Dinosauria (Theropods + Sauropods + Ornithischians etc) died out at the end of the cretaceous, and all of their "bloodlines" ended *except for* one - which is a clade we call Neornithes.
Neornithes are simply one of many specific branches within Theropoda. All birds in the world belong to Neornithes, and they represent *the only* surviving dinosaurs (sadly)
For a breakdown - all birds are Neornithes, and Neornithes belong to Ornithurae, which include Hesperornis and Ichthyornis, that you will often see as examples of "modern birds" existing alongside dinosaurs, these two specifically oceanic birds from the Western Interior Sea (aka, "Ocean of Kansas" "Niobrara Sea")
Ornithurae belong to Ornithothoraces ("bird-chests") that also include the so called Enantiornithes ("opposite birds") an entire biome of small sparrow-like birds, perching, flocking, bug-eating, ALL died out and were supplanted by Neornithe descendants from ocean birds.
Ornithothoraces belong to Avialae, which include long-tailed birds such as Archaeopteryx and Anchiornis, and...
Avialae is the sister group to all of the famous "raptors", meaning they have a common ancestor placed somewhere to the mid-Jurassic, where they fork into two branches. Together, they form Paraves.
Paraves + Oviraptorosauria form the clade Pennaraptora, which belong to Maniraptora (includes Therizinosaurs and Alvarezsaurs)
These all belong to Coelurosauria, which includes Ornithomimids and Tyrannosaurs - and as we climb further down the stem of this classification-tree, you'll notice we include more and more Theropods, untill we reach Theropoda itself - which is a sister-group to Sauropoda, and those together are grouped next to Ornithischia (which include Hadrosaurs, Ceratopsians etc)
Hopefully, I didn't complicate this too much - but imagine Dinosauria as a stem, forking into two, then three - ONE of those branches equal Theropoda, and in the mess of branches - ONE stick is named Neornithes (the rest of the tree dies!
) and from THAT lone branch, sprouts all the new branches and twigs and leafs that are todays sparrows, ducks, albatroses, ostriches, colibris, parrots etc.
So, all non-avian dinosaurs would have some connection to todays birds, in that they would have been more or less related to them, depending on taxonomic position, I guess - but only the direct descendants lend their DNA to modern birds (which would include early-mid Jurassic maniraptorans)
(This also means, Tyrannosaurus never evolves into a bird, neither does Velociraptor, but a very very close relative OF Velociraptor become todays birds. It also means "the chicken" is *not* special, as mass-media sometimes portray
ALL birds are equally Neornithes - a branch of Theropoda)