Pedal #1 was repaired by Greg Michalik from Guitar Aid London around 2007-2009. It was brought in by a German guy who said he bought it in Central / Eastern Europe a long time ago.
Pedal #2 was owned by Michael Lamb for over 40 years. He bought it from a musician named Otto Laier III in April 1969 (together with a 1965 Rickenbacker 360/12). Otto Laier served in the US Army for 2 years in Bolingen, near Stuttgart, Germany. He mostly played Kingston Trio style folk music, but he was also interested in psychedelic rock, being influenced by Roky Erickson who he went to school with. He started playing in that style shortly before he left Germany (in June 1968) and he probably bought the Maximal pedal at Radio Barth in Stuttgart in the first half of 1968. O.J. (as Otto prefers to call himself) remembers that store as an electronics store that had several floors, with music stuff on at least one of them.
Pedal #3 was sold on eBay in July 2013. A previous owner painted it and it looks like the switch was replaced.