Would I be correct to say the writers of confessions like the WCF had different understanding when it came to eschatology (some also believed in "presumptive regeneration" and a few other things. However, the wording they settled on was a compromise to show unity in what they could agree on?
Anything else that can help me understand this aspect may be helpful.
I am not sure what views the framers of the WCF held among themselves. My guess is most would have been Postmillennialists. I no nothing as to what any of them believed in regard to presumptive regeneration. Jonathan Edwards (October 5, 1703 – March 22, 1758) was 60+ years later and originally was a Congregationalist. He later changed to Presbyterianism c. 1751. Many, including myself consider Edwards to have been a Puritan and who was strongly opposed to the error of presumptive regeneration. Further he objected to the view that baptized infants should be allowed, at age, to partake of the Lord's Supper. His views on children and especially tests for membership were carefully set for in his two comprehensive works, "Distinguishing Marks" and later in "Qualifications for Full Communion", which I personally have truly enjoyed reading. All that to say that it is very possible that some/many of the men who deliberated on what to include in the Confession would have been of the same mind as Edwards.
Lastly, I would not say that what was finally included in the WCF was the result of "compromise to show unity". One of the hot disputes among the members was in regard to the atonement. There were a few who held to Amyraldianism and some who insisted that their universalist views on the atonement were not Amyraldian... which was more semantics than any real difference. However, there was no compromise among the members on this matter and their view(s) were rejected by a large majority and thus there is no room in the Confession for anyone to try and use it to defend any other view. The same was true in regard to the subject of Supralapsarianism vs. Infralapsarianism. And again, the Infralapsarians won the day and thus the Confession espouses that view.