I suspect you're correct about no militia unit at Huron. In June 1812, as part of Meigs' call up for Hull's campaign, the Western Reserve contributed 3 militia companies: John Campbell's Portage County militia, Thomas Rowland's Columbiana County militia, and a third one whose name escapes me. (I'm in Afghanistan and am writing from memory). Meigs ordered the 3 companies to Sandusky to guard the public stores there. Sandusky had been the location of a trading post since before the French and Indian War and the public stores were probably for trade with the Indians in the area. But, since flour was an important comodity, it was important to keep it from the British. Campbell's and Rowland's companies arrived in Sandusky in early July; the other company was already there with orders to strengthen and protect the post at Sandusky. In early August, BG Hull ordered Campbell's and Rowland's companies to Detroit. The two units linked up with Henry Brush's Chillicothe company, but never made it past Frenchtown. After Hull's surrender, MG Elijah Wadsworth, commander of the 4th Division, Ohio Militia, ordered out all four regiments of his division to protect the Western Reserve. Simon Perkins and Reason Beall's brigades bore the brunt of the task with Perkins' command positioned along the Huron River. It's not clear (or I just don't rememer) if Camp Avery and the Sandusky station are the same place, but I don't think so. I think Avery was further upstream.
Anyway, with that as a rambling introduction, it's possible that there was some sort of home defense unit in Huron at that time. At the Rapids, for example, about 12 men comprised the "militia", but they were apparently not part of any battalion/brigade/regiment/division. The point is, whatever defense force existed at Sandusky prior to 1812, it's likely that it was not officially part of the Ohio militia and won't appear on any muster rolls.
Have you visited the Western Reserve Historical Society? If not, I'd encourage you to look at Major George Tod's papers (some are available on line in the various Western Reserve Historical Society Tracts, 1873 and later); the David Trimble papers who was paymaster at Avery; and MSS 660, Collection of Papers, War of 1812. Finally, the Trump of Fame (newspaper), also at WRHS, may provide some clues.
I regret I can't provide more than just some peripheral information, but I hope this little bit helps. Good hunting.