Well if one is to believe the liner notes they were all recorded on the same days. Also, I don't think these were "rehearsal tapes". Why would the musicians travel so far to rehearse when they had a gig that night? And (again) according to the notes, Impulse was pissed at Thiele for spending so much money recording Trane. They wouldn't have been happy paying to record rehearsals.
My guess is that they went into the studio not to make a thematic album but to lay down some tracks that would be released on perhaps more than one Lp. (Even Ballads was recorded over three different sessions, on two of which other things were recorded. )
In a 1968 interview in Coda Thiele said: " The material that is unreleased is from the period of 1963..... This unreleased material is not inferior, it is just that he became quite busy in the studio. " (He also talks about material from California. Anyone know what that might be?)
OTOH, there are two cuts where Trane seems to go slightly off mike at the end of his solo as if he were turning to Tyner to indicate it was the pianist's turn to solo-- not something you would expect in a recording session.