I have two feature classes, one is in NAD_1983_UTM_Zone_17N (FEET) and the other is in the same projected system but only in METERS. I know that copying and pasting from one coordinate system to another without re-projecting can cause errors. However, does that apply when its just the Linear Unit that is different between the two? Can I copy paste the Feet into the Meters feature class without any issue occurring?
I would definitely project it into the metre coord system. The false eastings and northings let alone the metre foot difference mean the spatial location would be way off. What you mean by copy and paste I'm also not sure.