ESB has mono and production documents indicate one done for ROTJ-additionally Raiders had a mono.
It is correct that the 70 and 35 Dolby tracks are likely very much the same but until we get actual concrete evidence it’s impossible to say. The baby booms were filtering out the low end as opposed to an actual dedicated LFE channel. I will suggest that there are likely a few differences in range etc since the 35 was intended for optical and the 70 had mag tracks.
The definitive collection 93 mix was reputed to be derived from the 70mm mix before those changes were made and is what HairyHen has been working with.