After some sleuthing on the net I may have an answer to the Detroit stuff on Track, why/how. The case may not be totally sol-ved as Clouseau would say but here are some clues.
In 67/68 Lambert & Stamp were in New York and started doing some work with Patti Labelle's group, which we all know had several different names over the years Blue-bells, Labelle etc. Nona Hendryx, a group member, was Jimi Hendrix's cousin so maybe that's how they hooked up. The group were experimenting with funk/rock at the time, and while in New York Lambert/Stamp were also doing some work with The Parliaments. In the early sixties George Clinton worked in a hair salon in New Jersey called the Silk Palace and had Patti Labelle and Nona Hendryx as customers, so they must have been friends for years. Thereby giving us the Solid Hitbound connection.
Edit.
More sleuthing reveals that The Debonaires first Golden World single was arranged by Sammy Lowe (A Wingate Prod.), who is named on all the Sandpebbles Calla releases along with Teddy Vann, so there's the connection for the Sandpebbles Track release.