The 'A' stands for Alternate Captain, not Assistant.
Varone may have played against s crap team/goalie, but he played the best against them, among a lineup full of players intending to make a case for being in the lineup. He hustled all night long. They put him out to kill a penalty, he does all the work on Puempel's shortie. Given our forward situation (Mac, Lazar, Stone) I'd say he's earned a few games.
On the other hand Paul was picked as their best player in the rookie tournament and was the hardest worker at the DC. That earned him an extended look, most likely.
Read something about Mac but it was a French headline and I didn't click to read the full article but it appears it's not as bad as before. Still think he should hang them up.
Last point -- that hit may not have been all that bad, hard or nasty, but this is an intrasquad game and don't forget that Sieloff was playing D -- that's a long, long way to go to make a hit. You don't make those kinds of hits on team mates; they are not necessary. Plus he's a big guy and he got Mac shoulder to the head and then drove him into the boards. They simply need to get rid of hits like that (up high, against the boards). If the player is too tall to deliver a shoulder hit without head-hunting then he should use his hip. A small player is not allowed to hit below the knees (clipping) regardless of how short he is.