I think some of your comments are confusing people, as well as your discussion of stupid gaming mechanics.
The Varangian Guard actually formed in the 9th century - mainly consisting of Scandis and some German people, so around the time of this 867 start. You get an event and then can form the VG shortly into the game. The VG starts as Norse/Norse and reside up North. There are ways to convert them if you wish.
Also, as in history, Norse warriors (including some nobles) left home for the VG and often came back very different or not at all, so it is not out of the ordinary to have Orthodox men return home and, if noble/landed, possibly convert some. I think it would be hard in this game for that to happen unless you forced it though - which I think the poster above was trying to convey.