[Kuruharan]

I would consider the Light to be the embodiment or manifestation of Eru

There's that word "embodiment" again.

I'm afraid my reading of the quotes I cited above won't allow me to accept that Eru is present in any way that the Children can perceive. They can see the light, so I just don't think that light can be anything other than a created thing.

And there is textual evidence when Gandalf says he is "A servant of the Secret Fire". Why would he be a servant of anything less than Eru?

Well, I don't think he would...but I'm not too clear on what you mean by this.

I'm not sure I'm comfortable with the Valar being able to render things holy. For Eru to be able to do this would seem right, but to enable a being which can take physical form to do this seems to pose too many potential problems. Would it mean, conversely, that Morgoth could render something divine? Yes, he does make Orcs and other evil or corrupt creatures, but are they the embodiment of evil much as the Two Trees might the embodiment of good? I'm more comfortable with the idea that there is only one source of divinity and that is Eru.

I don't see rendering something holy as being the same thing as making it divine. Holiness to me means making something pure (or something being pure) without any sort of taint whatsoever. Being divine means...being divine. I don't think it is the same thing.