[Dilettante]

Formendacil, I wondered that myself regarding if the tomb of Elendil was visited by the stewards after his casket was removed to Rath Dinen. One almost gets the feeling that by Denethor's time, the Stewards were no longer interested in keeping the kingdom ready for the King's return, but desired more to hang onto their own power, hoping maybe the king wasn't coming back. If that were the case, visiting the tomb of Elendil would seem pointless at best and hypocrisy at worst. In fact, by the time of LOTR when the king IS returning, most of Gondor seems to be ignorant of Elendil. Only Aragorn and his band of "Rangers" (Dunedain) seem interested in remembering or invoking the name of Elendil.

Also, what of the fate of Amon Anwar, the Holy Hill? Was it as hallowed after Elendil's casket was removed? Was no one but the king (steward) still allowed there?

As for the red glow with the Oath of Feanor and the Oath of Cirion. Perhaps both are a signal that Eru is witness to the oaths. With the first, Eru was witness to Feanor's oath and would hold him and all his participants to every terrible thing that was promised in that oath. (See the Noldor being banned from Valinor, constant pointless slaughter, ect.) With Cirion, Eru was witness and giving his blessing and approval.