Jamieson, Fausset and Brown on Philemon 1:5

5. Hearing--the ground of his thanksgiving. It is a delicate mark of authenticity, that he says "hearing" as to churches and persons whom he had not seen or then visited. Now Colosse, Philemon's place of residence, he had never yet seen. Yet Phm 19 here implies that Philemon was his convert. Philemon, doubtless, was converted at Ephesus, or in some other place where he met Paul.

love and faith--The theological order is first faith then love, the fruit of faith. But he purposely puts Philemon's love in the first place, as it is to an act of love that he is exhorting him.

toward ... toward--different Greek words: "towards" ... "unto." Towards implies simply direction; unto, to the advantage of.