Losing Tanev would hurt horribly and he'd be pretty hard to replace IMO, so I'd like to keep him if we can, but things will definitely be tight. Stecher is probably gone unless he takes a big discount. Sutter is still under contract for another year after this one, so unless we can find a trading partner, he won't be gone (though he could be plausibly bought out). I think Sutter's a terribly underrated player, but he's still being paid a lot and as such, probably has very little value on the trade market, so I don't think he'll be easy to offload.
On the topic of Virtanen, he's already almost a 50-point player. He's on pace for 46 points (24 goals, 22 assists) in 82 games.