The Lion at Chaeronea was a cenotaph not a tomb.
We keep using the word 'tomb' for Amphipolis - first the Lion Tomb, now the Kastra Tomb ... - but one interesting feature is the lack of a door. It may have been removed when the structure was sealed, but the lack of a door so far suggests the lack of a burial, and in conjunction with the steep steps this to me suggests increasingly that it was not a tomb but possibly a cenotaph or more likely a heroon.
Obviously it is too early to know for certain, but I am putting the suggestion out there.
As Shakespeare said:
What's in a name? that which we call a rose
By any other name would smell as sweet ....I've maintained for quite some time that the colossal size of the structure suggests it was very unlikely to have been built for anyone other than Alexander the Great. Although the Mausoleum of Augustus was round, and seems to have copied it, there is a dearth of round Greek tombs; the shape was previously restricted for very important structures, many of which had cult purposes ... and the prime example was the tholos built by Philip II at Olympia and filled with family portraits.
It was filled with portraits by Leochares, who had previously worked on the Mausoleum of Halicarnassus and created portraits for his successors Idrieus and Ada of Caria.
The round shape of the Amphipolis structure, the lack of a door and the sources which all say Alexander was buried in Egypt, to me all suggest that it was more likely to have been a heroon or cult of Alexander the Great with or without his ancestors and relatives, whatever it started life as.