Either way, it's going to be weird for Twilight. I thought of a couple of different ways to put this in to the comic. I did the whole "sandwich" scene on page 2, but I've got a couple more bits planned for later pages.
In all honestly only used Lyra because I already had a vector for her from a previous comic, and didn't want to do a whole new one. I don't think that I have any other Unicorns on file, except for her, Rarity and Sweetibelle.
It was a little difficult finding examples for this comic as we rarely actually see Unicorns doing anything more than "fetching and Carrying", so in the end I cribbed Spikes lines from Boast Busters as that was all that I had to go on.
But ... Lyra is one of my top ten ponies. I've added her in as a cameo in a couple of my comics, and I've got one or two dedicated to her as well.