ok on the topic...
yes just mix everything up, who cares? washing is washing... where got so much time to even go into the nitty gritty of mixing this and that. the only concern is perhaps no new clothes in case colour runs... or kids clothes wash separately due to chemicals... or delicate clothes wear separately to avoid damage...
concern of washing clothes is Clean, and undamaged. not abt who feels how it should be washed... seriously, got pple so free to fight over such matters meh?