Simeon is not a person from the Old Testament. If you mean Jacob's son – then yes, but not the last one. This Simeon, who was old and recognized Mesiah in baby-Jesus is from New Testament.

I don't know if connecting Veles with "prophecies" is adequate, but I cannot say it is not, neither. If we connect prophecy with magic, then yes.

Here you have one description in Polish:

U ówczesnych Słowian miernikiem bogactwa była ilość bydła. W tym świetle zrozumiałym jest opis daniny, którą litewski książę Kiejstut złożył w 1351 roku podczas zaprzysięgania umowy z Ludwikiem Węgierskim. Litewski władca kazał wtedy przyprowadzić czerwonego wołu, uwiązać go między dwoma słupami, po czym rzucił w niego nożem myśliwskim, który przeciął zwierzęciu tętnicę szyjną. Następnie Kiejstut i jego ludzie pomazali swe twarze i ręce bydlęcą krwią. Taki krwawy obrzęd towarzyszył podejmowaniu wielu ważnych zobowiązań.


It says (of course my amateur translation):

Slavs from the past considered a person "rich" if they had multiple cattle. According to this we can understand the description of a tribute that Lithuanian prince – Kiejstut – paid to Ludwik the Hungarian in 1351. Lithuanian ruler ordered to bring a red ox and to tie him between two poles. After that he thrown a hunting knife cutting his carotid artery. Then, Kiejstut and his men painted their faces by ox's blood. Such important ritual accompanied to important pacts.

In the next parts of this site there is written, that the holy place of Veles was Szczecin. Ebon said that there were three hills, from which the medium sized and the highest one were devoted to Trygłów (Three-heads is a West Pomeranian name of Veles). His priests said that he has three heads because he ruled in three kingdoms – heaven, earth, and underground.

However, there is no written information about how people worshiped him and the author assume it was quite the same like with other Slavic gods. Every Slavic tribe had its own sacred place, where people were gathering. Our ancestors were not building any chapels (buildings were rare) and they were praying under the sky in the groves or on the hills, as they respected nature. Slavs worshiped their gods mostly by giving the offerings in animals, food and drinks. They had feasts, they were singing, eating, dancing. And authors assume it was quite the same in case of Veles.

Then there is written about Rus treaties with Byzantine – that "Vsya Rus" made an oath in name of Veles when they were taking some pacts, or whatever.

But at the end there is written, that Veles still exists :D That is not all. That Veles has his private vendetta on Poles that they do not pray to him, and now he live in human shape. In a shape of our prime minister, Donald Tusk :p