I am descended from Sebastian Medlar who's name was bastardized when he joined the Continental army from Metler (or Mettler).Here's what I have on Medlars in no particular order.
In 1776, the state of MD conducted a census.In Frederick County, the Elizabeth Hundred area (near modern day Hagerstown MD in Washington County), there were five Mettlers, Sebastian age 15, Henry age 14, Jacob age 60, Magdalene age 48, and Margaretha age 12.Unfortunately the way the census was listed, people are lumped into male, female, and age brackets.There is no indication of household.However, given the complete lack of other Mettlers in the area, I've always assumed that these Mettlers were of one family.They most likely came from some area of Germany since in the 1770s, the Hagerstown area of MD had been settled predominately by Germans.
Other Mettlers or Medlars I've found have been:
George Mettler, Philadelphia, 1761 (Berks County PA Naturalizations, pg 45, State Geneaology Society)
Catherine Medler, 1745-1747 came from Bohemia or Morovia.
Jno Medler, VA 1667-68, pg 31 of Nell Nugent's "Colonist and Pioneer's Abstract of VA Land Patents and Grants"
John Medler, MD 1674, pg 312 MD Land Patent.He was transported over in 1674.
A John and Hannah Medler are listed in St John's Church Book in Hagerstown as having two children:Hannah born 27 October 1797 and John born 21 August 1799.
My Sebastian married a Sarah Greene and they both eventually moved to the Charles Town area of Jefferson County VA (now WV).She died in the 1820, he died in 1832.He spelled his name Medlar after the American Revolution.They had 4 children that I know of:William, Henry Edward (mine), Mary Jane, and Elizabeth (who married a Johnson).
So, while I've read about the Novia Scotia Medlars for year, it's been pretty clear that at least the MD branch decended from Mettlers who came from Germany in the 1700s or prior.