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.
The way this line looks, I say only keep 3 or 4. I heard a very funny story on radio yesterday that reminds me of the Steelers OL. I don't remember the name of the player telling it but he was a LG at Notre Dame, who later went on to play in the NFL.
During practice He lets Oliver Gibson by, and Gibson blows up Dorsey Levens in the backfield. Coach Lou Holtz shouts down and tells the guard to get off the field. He then tells the players to line up and run the same play again. The left tackle was confused, not knowing where to line up so he moved inside beside the center. Holtz told him to move back into position as if the guard was still there.
They run the play again, and again Oliver Gibson broke through the line and hammered Levens. Holtz then yells to the guard who was sitting on the sideline "See, you play like that and it makes no difference whether you are on the field or not!" That is how I feel sometimes watching the Steelers OL.