How to Spot Lifeform eggs on the Marine Side:
1) The Commander can spot it by Different HP values:
skulks eggs have 120, gorge 140, lerk 160, fade 180 onos 320-360ish
maybe starts at 120, but it's +20 per, I'm forgetful (c) kmacg
2) On the field - if you have structure hp numbers enabled by hp of the egg.
3) Of the Egg icon on the map its a different icon then other eggs, very distinct
4) Lifeform eggs can be spotted trough the Steam friendslist because of friendshighlight (can be enabled in the ns/ns2+ options.)