After Uncle Dan's passing, Frank Lefever took the single barrel parts and moved down to Wheeling/Moundsville, West Virginia, and became plant superintendent of the Three-Barrel Gun Co. Charles F. (Fred) Lefever and probably some of the other brothers finished up some of the remaining materials of D.M. Lefever Co. and marketed the results under the Waverly Arms Co. name. I've also seen doubles marked Waverly Arms Co. that look like the lower priced Union Model 21 --
In fairly short order Fred went to work for Union Fire Arms Co. in Toledo, Ohio. Fred designed the single trigger used on the Union --

Union Fire Arms Co. eventually became, or at least used the name, Toledo Arms Co. and Charles F. (Fred) Lefever went on to have a 42 year career with Daisy Manufacturing Co.
This is how I understand it went. Any clarifications, additions and/or corrections welcomed.