This is the only episode where Miroku is voiced by his original English dub actor Kirby Morrow prior to his passing on November 17, 2020. For Miroku's later role in the series starting from Sengoku oishî hôshi (2020), Ian James Corlett replaces him as the voice actor for Miroku in the English version.
"Inuyasha: Since Then" was a special chapter released after the 2012 earthquake in Japan, to help raise emergency funds. Here, the start is reworked to fit into the Yashahime narrative by allowing Root Head to survive and latch onto the Sacred Tree.
Towa is only captured due to circumstances set up by Riku (who is introduced later) and Moroha.
The bike seat was likely found by Mount Hakurei, as that's the last place Kagome ever rode a bike in the series; she was always carried by Inuyasha or Kirara after that. She lost the bike when Mukotsu of the Band of Seven attacked.