User blog comment:Xilinoc/Ch. 644 - BABY, HOLD YOUR HAND 7 (Never Ending My Dream)/@comment-5303512-20150924113750/@comment-26091912-20150925000629

@CNBA3 Ichigo's father being the former 10th Squad Captain is only relevant to Ichigo—not Toshiro or Rangiku. If Isshin didn't go AWOL, Ichigo wouldn't have even been born.

On your second point, if I recall correctly, Ichigo spent a week with the 11th Division in Soul Society (sparring with Ikakku). The only interaction we've seen with Toshiro, Rangiku and Ichigo was in the real world during the Arrancar arc.