WikiTree is certainly based on having sources to back up the posted facts. Glad you're being sensitive to this, since ancestors from the 1700s and earlier usually have other WikiTree members interested in their profiles.
You're right, you might have valuable information that provides a "lead" for the other researchers. In these circumstances, while in EDIT MODE just below the == Biography == you can create a section == Research Notes == . In this section you can post your information and discussion. I frequently do this for my family "brick walls". In that section you can also provide links like [[Doe-12345|John Doe]] to possible children, parents, siblings etc..... if there's not enough evidence establish a relationship yet.
Enjoy your research!!!