I wouldn’t recommend planting sweet cherries in central Illinois unless you are a really dedicated hobbyist. My sweet cherries are doing okay but I am having some problems with canker on some trees and insect pressure is pretty high (mainly plum curculio). I have been able to control brown rot with a combination of Captan and Indar.
However, if you have a strong interest in sweet cherries you could try WhiteGold or BlackGold which are both self-fertile and are good choices for our area. But I would read this thread- it explains the problems you would face.
Your orchard is actually good sized with fairly large trees. I have more trees but most are dwarfs with some semi-dwarfs and one standard size tree.
In central Illinois apples and tart cherries will do well. It does help to have varieties that are disease resistant.