So, the Overguard applied by Light Verse and Triumph behaves a bit strangely when applied to certain non-player, non-companion allies: IE, rescue targets, railjack crewmates, Eidolon Lures, kavor defectors, operative defense targets/chipper, etc.

It will only apply Overguard if the target doesn't already have Overguard. So if you can cast your two Light Verses before getting into range of your target, you can apply the much stronger Triumph to them- although they will not receive the ability to regenerate Overguard even if they are capable of getting kills. They also won't be healed by Light Verse.

If you want to use Dante to "heal" those particular allies, preemptively preparing two Light Verses and waiting for their Overguard to be lost before casting Triumph works reasonably well- I can comfortably solo Trilodons while keeping the lures alive this way. Unfortunately, in cases where the UI will show the health and shield of, say, a rescue target, it won't show the Overguard they possess.

Also, for some reason, converted Liches/Sisters as railjack crew can't receive Overguard this way at all. Though they don't really need it, in my experience.