There are plenty of SP's for the Cubs to acquire. Realistically all of the following are available for the right price:
MacKenzie Gore, Joe Ryan, Sandy Alcantara, Merril Kelly, Zac Gallen, Michael Soroka, Charlie Morton...
Those are just a few off the top of my head and at various levels of ability. Some are buy low (Morton./Soroka) who have pitched better than their ERA suggest. Gore is a top-line pitcher who would cost a ton. All could be acquired using the system the Cubs have.
Outside of Suarez, what difference making hitters are available? Most hitters are complimentary and the Brewers would get better by getting a Willi Castro or whatever, but he won't transform the team, either.