I have extensive experience in genealogical research and have been examining the Usilton families from Maryland. It is my expert opinion that enough information exists about these families to tie them together, but the critical evidences that will connect the dots will only come from researching gravesites and finding the remains of families history in any living descendants, threatened to be lost as time goes on.
There are uniquely two clusters of Usilton families 1) an older family that can be dated back to the 1700's and are found clustered in Kent County, MD. 2) a family from Queen Anne's County, MD found in the 1800's. These families are both likely related but making the connection is difficult because Census records and the like can only provide us so much information. The fact that all Census records for 1890 were lost in a fire is a struggle for many trying to trace their modern families back in time.
The missing connections are few and I believe that visiting the cemeteries were these Usilton's are buried and recording all buried under the name Usilton or the like, with complete headstone transcriptions, and attempt to uncover who purchased the lots and when, will provide these final key evidences. Anyone living near these cemeteries or passing by on route somewhere that can aid in assembling this information is needed here. Find-A-Grave online has some Usilton's in their index, which can tell us some of the cemeteries there are Usilton burials but these lists are not complete, such is the case I know for sure with Church Hill Cemetery in Queen Anne's, MD.