I use shampoo as shower gel most of the time. I wash my hair and then realise I’ve got loads of it still knocking about so just lather on down. Used a bar of soap to wash my hair loads of times too.
I’ve used very cheap washing up liquid to wash hair and body before. Not recommended.
Pretty sure I’ve used hand soap to do the washing up. Fine as long as you rinse as you go.
I use bathroom/kitchen/surface cleaner all interchangeably obviously. If there’'s a difference I have no idea what it is.
Think I might have put Ecover washing up liquid in the washing machine once.