I do think Toronto has the best shot at signing Stamkos but not at a discount like 9.5mil. with Canadian tax he'd lose quite a bit more. I'd say it's 10.5 or he gets 10.5 somewhere else.

This Canadian tax situation isn't really a issue for players.....especially those making huge money. They are incorporated companies, which has a tax rate of 15%, it's 35% in the US, and this is just for "profits.
The money that players take out for spending...is taxable at the personal tax rate, but most of their money is their "company" I know an NHLer who has not spend any of NHL salary in 12 years in the NHL. He lives off the ancillary incomes that players in the league make as a group and other money individually. Doctors, dentists, lawyers, entertainers do not pay taxes like most mortals.
Leafs can get rid of Holland, just not by offering him a contract when his current contract expires. Bozak at 4.25m a year for two years, might be good value but still might be tough to move without taking money back.
Personally, I hope they do not sign Stamkos. Let Reilly, Nylander, Marner, 1st round pick this year become stars and get the big money in a few years. Don't need Stamkos gumming up the salary cap in the future.

Problem is US tax and Canadian tax are totally different. In Canada, incorporating is generally better. In the US it is often the other way around. I'm no expert but the taxes do matter. There is a reason agents and teams have spoken publically about it in the past. The MLB has had serious issues with this and contracts with tax clauses to be made whole.