I would keep 7 - there are needs at TE and RB, and there is depth at LB and DL. The Steelers will only dress 7 lineman, so I would go with the starters and Beachum and Malecki. I'm not a fan of Malecki, and would prefer a veteran interior swing guy if there is anybody capable out there, but I think he makes the squad. I would keep Long on the PS and either add a cut to the PS or keep on of the other guys.
If the Steelers keep an 8th, I would go with Long over Whimper, but don't feel particularly strongly about it either way.