I've explained several times my proposed timeline for the Kasta mound at Amphipolis, but to clarify it again for people:
320s BC built for Alexander the Great and his family, which possibly included Hephaestion.
323 BC Alexander dies and on his way back to Macedonia to be buried Ptolemy hijacks the body; work continues on the tomb, and the hope of his heirs is that they will get his body back. That never happens, and either the tomb is left empty or re-used by a later ruler.
The mound on top of the tomb is too heavy and the weight starts to cause structural difficulties - as with the Colossus, thinking big was all very well but things went wrong when they didn't have the engineering skills to put ideas into practice.
The first step was to try to erect scaffolding inside the tomb to support the roof, and this may explain the hole in the mosaic - it was a post hole for a wooden beam.
That proved to be insufficient to stop the architectural members from continuing to move, so the decision was taken to fill the tomb with soil and build rough walls to hold the soil in and support the roofs so that they would not cave in.
The next step would have been to remove the superstructure to alleviate the weight bearing down on the tomb, in anticipation of being able to remove the soil and re-open it. That step didn't work out and the tomb was never unfilled.
The brilliant archaeologist who found the tomb and has done such amazing work on it has already presented the dating evidence for the removal of the superstructure. It was originally assumed to be Christian anti-pagan iconoclasm, but the finds in the layers were Roman - and could date to as early as the second century. These finds indicate work of some sort taking place at the site, but need not be the date at which the Lion was removed.
My interest in the site began in the later 20th century when I included the Lion Monument amongst those I covered in my PhD.
At the time the Lion was being down-dated to the Hellenistic period based on the archaeological context and finds, although the style or the sculpture and the design of the architectural support seemed late 4th century BC.
The problem with the Lion Monument and the reason why it was not linked to the Kasta Mound for so long is simple: it has real Hellenistic foundations, and the monument was erected in the Hellenistic period.
This may seem strange, but there are a number of buildings that were moved and rebuilt in the Classical and Hellenistic periods - quite a few are in the Agora in Athens, for example.
Going over the chronology of the Lion Monument rather than the mound, it seems that although the Lion and its architectural base were created in the later 4th century BC, it was moved not long after and re-erected as a new monument at a different location.
So now I wonder if the Lion and base were removed from the mound as a first step towards stabilizing the chambers within the Kasta Tomb, and whether the attempt to fill in the tomb with soil was a second step.
To make a few quick points:
Although internal doors have now been found, the anteroom and the steep steps still speak to me of cult as much burial, and I believe it's a heroon as much as a tomb as was the norm for great rulers of the time.
Hades and Persephone were common funerary motifs. I know a lot of people like to talk about "Orphic" cults but although these existed, they were not as important as some scholars like to make out. In the 19th century anticlerical scholars emphasised them to try to create 'antecedents' for Christianity and some today seem to go over the top seeing Orphism everywhere partly because they are disillusioned with Christianity. Yes there were Orphic cults, and yes Olympias seemed to belong to a cult although much written about her is propaganda. Alexander, although he saw himself as a living god, preferred more mainstream religion.
I am aware of the flashing eyes description of a lion, and it is possible that the something was inserted into the eyes of the Amphipolis Lion, but lions with hollow eyes such as the Cnidus Lion fit better.
The name Eurydice is less to do with Orpheus' Eurydice and more to do with Eurydice of Argos, since the Argead claimed descent from her family at Argos.
The Argeads also claimed descent from Heracles, and the inscription ΗΡΑΚΛΗΙ ΠΑΤΡΩΙΩΙ found in the strange tholos room at the palace at Aegae makes this clear. This 'tholos' room may have been a throne room or served some other purpose, but it was highly archaic in shape and kept even when the rest of the palace was rebuilt.