It is not known whether the Avanties here are Gregory Dee & The Avanties from Minneapolis or the Avanties from Northern Minnesota (Ranger 1198; Next Door To An Angel/Denice) as noted in the liner notes.
Gregory Dee (ie Greg Maland) should have been with The Castaways by now.
The northern version was not supposed to be recording until 1970.
The possibilities maybe,1) that these songs were recorded Gregory Dee's band without him and never released it, 2) or the northern Avanties came to the cities (Minneapolis/St. Paul) earlier to record and did not release them, 3) or another band using the same name but again not releasing their work!
Time may tell us, but I'd say '1' is the most probable!