Orthodoxwiki points out that the sticharion is a variant of the baptismal garment, and is equivalent to the Roman Alb.
It also points out that it is normal for an ordained Lector to wear a cassock, but not vestments.
Ordained Cantors likewise “vest” in an Exorassion (over-cassock).
Some groups may vest them in a sticharion.
Ordained Acolytes and lay Altar Servers wear the Sticharion
Only subdeacons and deacons normally wear the orarion; the orarions differ in size and wear pattern.
Lay readers, from what I’ve seen and experienced, do not vest, but should dress appropriately. When an altar server is also the lay reader, he’ll be wearing a sticharion.
Given the materials in catholic doctrine, the sticharion would be appropriate, without orarion, for any lay minister. It is not, however, the current practice where I’ve seen.
It should be noted that, while the Ruthenian Metropolia of Pittsburgh permits minor orders, very few have been ordained, and fewer still for permanent service in the minor orders.
Current praxis seems to be only altar servers being vested amongst the laity.