How feasible would non-jawed vertebrates be on land?
In my alien world life has evolved very convergently with life on Earth. Carbon-based lifeforms managed to evolve multicellularity and evolved a lineage of organisms in line with early fish, however on my planet facial tentacles were favored rather than lost. As the notochord evolved and a skeletal system began to ossify, the mouth still utilized highly specialized tentacles. Some of these fish equivalents developed bony protrusions on their tentacles that were sharp or flat depending on the diet of the fish. Basically, these organisms became bony fish without jaws but very muscular faces. The various forms of tentacles acted as the various forms of jaws on Earth.
Eventually, some species made the jump from water to land, evolving in a similar manner to amphibians and eventually reptiles. In this scenario, there are no jaws in the skull. What would the skeletal mouth area of this organism display? I have some ideas such as: a much thicker, robust bone structure ensuring more muscle attachment points and/or a larger braincase for the complex neural needs for many tentacles.
Furthermore, if these reptile equivalents were to increase in size and evolve similar to dinosaurs or today's mammals would these organisms be able to thrive with this different form of oral intake? It seems that because of the tentacular mouth being a part of the common ancestor of all terrestrial megafauna it should be simply an alternative to jawed Earth organisms.
Essentially I would like to understand what bone structure would evolve and are there any factors of terrestrial life that would hinder the expansion of these jawless organisms?
Note: Chewing would be done through the use of the "teeth" that evolved on the inner layer of tentacles or through protrusions in the mouth itself.
EDIT: I guess what I would like to understand is what the ossification of a conodont-type organism's skull would lead to. Perhaps something similar to the lamprey's cranium with a support system for the "teeth" and muscles or closer to a hagfish with a less supported oral area? Seen here