We definitely don't want legionaireys claiming their role, nor their targets, in most cases. If two legionniries reveal targets, and one legionayre conflicts with the other legionirre, we really don't have anything actionable to work with. Certainly one of the two players could be a true leggionaire, but the other is just as likely to be a power role as they are to be mafia (2 of each). Maybe consider this strategy if one of the civ power roles dies, but not any sooner.
If a leigenneir role claims to avoid being lynched, assuming we trust them, we would still be just as likely to redirect the lynch to a power role than to mafia. Most likely, it would just hit another leyginoir.
As for lengineers claiming leiginner just before being lynched, and revealing their targets - potentially that has utility? Better than just dying a vanilla lerringer.