I think that Rephaim already have a section, and so Nephilim are basically no different in terms of cryptozoological legitimacy. The Nephilim are a historical mystery, and could be interpreted as being all manner of different sorts of entities - like aliens, true giants or even neanderthals. If you wanna make a Nephilim article, I say 'go for it'
Sweet, good idea. By 'cloaked humanoid' - Do you mean like the invisible-looking entities that resemble the alien from the Predator movie when it cloaks itself? Cos the 'Expanded Perspectives' podcast named that being 'The Glimmer Man'.