What salary cap problem

I'm not so sure you can put JT with that level of player. I get putting him at 3c to fill a role but Virtanen is god awful in fact I think he might get dealt for a bag of pucks.

Why would Seattle take Holtby though? Way better options for the draft

A few things:
1) Why is Seattle taking Holtby?
2) Are you sure Beagle is on LTIR? Because if not there goes your cushion
3) This team isn't good.
-Hoglander has had a solid rookie season, but he's scoring at about a 20 goal 35-40 point pace. That isn't really first line material.
-On your second line you have Podkolzin who has upside, but this year literally put up a third of a point per game in the KHL. Yes he's been pretty solid when playing against other juniors (not spectacular but solid), but pencilling him into NHL 2nd line duties and expect success seems like a huge over kill.
-On the other wing you have Pearson who has been like a 30 point player this year
-Motte is a fourth liner on the third line. Not awful, but given the rest of the offense, awful
-Virtanen is having a god awful year, can he rebound, I sure hope so for your team
-On D Juolevi in your top 4 is not good

Holtby is unlikely to get taken by Seattle, much more attractive options, that's another 4 mil, Beagle won't be on LTIR come next year that's another 3 mil, Hughes and Pettersson could very well demand more then that, that could be another 2 mil. That's 7-9 million extra then what you have accounted for here.

I get where you are going and think you are pretty close to correct but Seattle won't take Holtby