Yeah, if you use all oils, butters, your hair will be very, um, oily.
I've never made a conditioner bar, (I make a regular type conditioner) but you can add or delete ingredients according to what you like--and you can start off simple if you want.
I think you could start with the BTMS and cetyl alcohol with an oil and a butter and a preservative. then you can figure out what your hair needs and add ingredients as you see fit.