I'm sure that Haukur and Óskar would never seriously
converse in "reconstructed" Old Norse, unless they were trying
to show off ;-)
The difficulty (for the Icelander) of pronouncing Old Norse in
the "reconstructed" way, is that it is very difficult to do for
more than a few seconds without laughing!
In Modern Icelandic the difference between "ei" and "é" is
ROUGHLY the difference between the vowel sounds (in American
English) in "bait" and "beer".