Love that pot, good use of Scaveola! The exposure might help ID. No familiarity with the Salvia, but would expect to find it in full sun if it's like other Salvias. If it's a Perilla, it's got to be a pretty new one. The Perilla magilla I have takes about 3x as long as Coleus to make roots in water, which Coleus usually does within a week. Not had many Plectranthus, but I don't remember having any without a fairly strong scent (as I would also expect from a Salvia in my limited experience with them.) Any olfactory input on this plant?