I'm glad that this is helping you on your search!
Have you requested the court info? From the index, it lists Ann as the plaintiff and William as the defendant. Hmm... the plot thickens! I believe that can be requested from the IRAD Depository at Northern Illinois University (I think they have the Lake County stuff). I don't know if they also do the birth/marriage records:http://www.ulib.niu.edu/reghist/IRAD.cfm
If I go get a chance to go to the Lake Forest library, I can look at the Lake Forest paper to see if there is any info about the individuals in the time frames you provided.
They had the actual probate books at the Genealogy Society room and I tried to take pictures of the will for John Matthews (the book is huge) with my phone. I don't think I took very good pictures - I'm not sure if they turned out (I'm terrible taking pictures with my phone). I can go back and take pictures with an actual camera as they will probably turn out better. His son is mentioned briefly as living in Wisconsin. He did specifically disinherit two daughters.
Do you have any specific information about Frank? William's obit was kind of sad - he died alone. Do you know when he was born for certain? Unfortunately, the obit didn't give much information. It would be interesting to see what information is in the court documents!
I hope that you find everything you're looking for! Let me know if there is anything specific you want me to look up. I may not be able to get to it immediately, but I can generally get to the libraries on my days off of work when the kids are at school/daycare or if I leave them at home with my husband in the evening! :-)