Still 80% now for winning the NL Central. If they lead by 3 games heading into the final week, that probably goes to 95+%.
Cubs may miss Gallen and Kelly, but they'll also get Keller against the Pirates, who have been playing solid ball lately. FWIW, it's the Brewers who have the slightly easier schedule by W%. Though, it's pretty much even as you state.
If the Cubs win the division, it'll be because they've earned it by playing better against a similar schedule.