I add the eos just before pouring into the bottles (warning, go light) and will occasionally use joboba in the soaps - in fact, thats the ONLY time I use it is when I'm making soap for shampoo.
Also, rather than water I will, on occasion and/or special request from my sister, substitute a chamomile infusion for the water but you could use any infusion I suppose. I've never tried milk of any kind, not sure if it would curdle or not and don't really want milk in my hair.
I run it through soap calc, and use about 1 oz per 2lb batch (the rest is oo). I'll also add 1 tbs white sugar ppo but thats just habit and I like the lather it creates.