Schneider definitely belongs in the top-6, DeSalvo and Catenacci however, does not.
I don't know about DeSalvo. 40 points in 66 games as a rookie pro last year. 40 point seasons in the AHL are pretty good. For most teams that's a 2nd line player. He's small and on an AHL contract but he's not exactly a non-talent.
When I look at some of the changes to the Hartford roster from last year--the loss of Hrivik, Beck and Jensen who were their best offensive players---the Rangers obviously did not want to repeat another last place finish with a team that was extremely challenged to put up goals. That's why the firing of Gernander and the signings of Schneider, Carey (another point a game player), Whitney (who had an off year offensively but a lot of past success), DeSalvo (a youngish guy who had a productive rookie year). Instead of Carey they end up with Puempel--at least for now. They might have Carey too after Fast gets back. Kosmachuk and Catenacci have been around too--probably better suited as third liners. Selleck is muscle--and the AHL is a nastier league to play in than the NHL. Truth is you don't want Ryan Graves being your go to guy when it comes to defending teammates from legit goons.
I'll note that I was more impressed with what I saw from Tambellini than Gropp in preseason. Gropp is very important in the Rangers future plans though so I think he will get a fair shot. He's got a sneaky release and a knack for finding soft areas. As for Nieves the main thing is he gets ice time. He looks more like a checking forward than a scoring one. I'm not worried all that much about his offense because I see him in another role.