There are many surfactants that might work to solubilize/micro-emulsify oils/butters into a surfactant solution and produce a clear product. There are even more that would simply macro-emulsify them and produce an opaque product. We’d need to know your definition for “natural” to recommend one, though, and it would be much better if you’d disclose more of your formula.
One of the things to recognize is that you’re using the term “emulsify” somewhat incorrectly. To emulsify is to take two immiscible phases and mix them together to form a uniform product with droplets of one phase dispersed throughout the other phase. You’re already getting that, but your emulsion isn’t stable, which is an entirely different problem from not emulsifying at all.
To determine if you are getting benefit from the oils/butters, make three batches without the Guar. One with no oils/butters, one with 1/2 your usual amount, and one with the full amount. Try them on your own hair, and give them out to other people to evaluate blind. If no one can tell the difference between the three, your not getting any benefit, but if there is a clear improvement as you go up in concentration, then you are. But if If no one can tell the difference between the half concentration and the full concentration, then you are getting some benefit from the oils/butters, but you’re using at least twice as much as you need to be.
You could also send the shampoos out to an analytical lab for analysis, but that’s probably overkill.