Not very likely. As those articles mention it's safe to say that Alexaneder was buried first at Memphis and then at Alexandria. The Ptolemaic rulers of Egypt actually got a great deal of prestige out of the fact that Alexander found his last resting place in their capital. The highest religious office in their kingdom in fact was the priest of the deeified conqueror. Later several prominent Romans would visit the tomb in Alexandria.

On the other hand there is absolutely no evidence for the claim that the newly discovered tomb in Amphipolis is that of Alexander. It seems to roughly belong into the time of his death and to have been intended for a high ranking individual but that's all for now.

I have to say the kind of sensationalism that the first of the articles you linked displays is quite unnecessary. The discovery of the tomb on its own is spectacular enough and there is no need to imply that it belonged to Alexander.

From the Archaeologists point of view who excavate the site.

The tomb possibly belongs to one of Alexanders generals.

And there is the possibility one of Alexanders tombs to be in Amphipolis.

Amphipolis was the second most important city after Pela the capital of the Macedon kingdom. A very important trade cender that was nicknamed the city of nine roads, rich in culture and a strong naval port. It was there that the fleet of Alexander the great started their road to Asia. Also there was the birthplace of three important admirals Androsthenes, Nearchos and Laomedon.

The tomb itself is a major finding on it's own. Constructed with marble imported from the island of Thassos. No matter who is buried it was an important figure-es of the past and now remains to be seen in what condition is the tomb inside. The damage at the sphinxes indicates that the Archaeologists weren't the first to find the tomb.

You can see some info here