Donaldson, Machado and Harper are likely to resign with their current clubs by that time. With all the revenues around, no way any of them reach free agency--no way Toronto, Baltimore or Washington give up their franchise players easily. This isn't the early 2000s..
Judge and Sanchez aren't sure things, with Judge's K issues and Sanchez's D..
And FYI, the Yanks don't have that kind of money--due to poor attendance, luxury tax issues, Yankee Stadium mortgage payments and huge revenue sharing bills, the Yanks can no longer afford to keep payrolls this high--I've heard that they're operating at significant losses with a $230-$240M payroll, and the Steinbrenners want to get under the tax, which is at 50% at $175-180M($189M with benefits), and likely to increase further next CBA.
In addition, until the Yankees show signs of putting a capable team on the field, free agents will avoid the Bronx. Look at the mess in LA and NY with the NBA's Lakers and Knicks--even with money, free agents won't go there because the teams stink.