Infernum - I've only heard the debut and it was nothing special. It features Rob Darken of Graveland and Capricornus of Capricornus and Thor's Hammer doing keys and drums respectively. But the main songwriter is some random dude that I believe committed suicide or some shit. ANyway, that album is very average and reminded me of a poor man's Celtic Winter. Get Graveland instead.
Iuvenes - not bad, but still of the Graveland school of songwriting. I haven't heard the latest two from them, so they might have improved and gotten their own identity.
You'd be best getting Immortal Pride, Celtic Winter, Following the VOice of Blood and Creed of Iron from Graveland than any albums from those two bands.
Haven't heard the other two, but I believe Wigrid is a Burzum clone.