I don't practice Reiki but my boyfriend is does, when you mentioned Reiki, I asked him & he gave me this information :
Are Reiki Guides Part of Usui/Holy Fire Reiki ?
According to Laurelle Gaia "The Holy Fire itself provides guidance." The purpose of spirit guides is to guide us to Source. Holy Fire is the direct connection to Source. You may find that guides from the third heaven (dwelling place of Source) may still bring you messages, as they are messengers of the Holy fire. If you are already working with with guides that are compatible with Holy Fire, you will still find them helpful. As in all phases of our spiritual journey, guides come and go as we heal and grow. From faq below:https://www.reikiclasses.com/reikiclasses/usui-holy-fire-reiki-faq/
Reaching for the Highest Heaven
Usui Holy Fire Reiki comes from the Third Heaven, or Highest level of heaven. The first heaven is the ordinary world, the second heaven is the land of nonphysical energies, including ghosts and spirits, the Third Heaven is the realm of God and the highest levels of spiritual energies. [More on the heavens from Wikipedia]
In my experience, Spirit Guides can be seen from time to time in Auras.
Best wishes <3