I just put together a list-building video explaining all my choices for the game, so there should be a great deal of explanation in there!
Short version, you pick the master before you know the opponent's master. For this round, there were at least 4 keyword models on my maybe list (and I would like to bring Allison 100% of the time if the matchup allows it), but.. Once he declared Ophelia I felt like most of my keyword options didn't work (and I explain why with each one in the video), so ended up with these all fixing specific problems.
I would have chosen Lucius for this round as I'm a lot better with him, but I played him a lot last month in Neverborn and people encouraged me to do a change of pace. I really like Nellie so wanted to investigate what I can do with her in a variety of pools.
That said, I rarely take that many keyword models, as I tend to like masters with weaker keywords. So a list with very few keyword models is pretty standard for me. I take whatever models I think will work in a given situation, and with card draw masters like Nellie, Lucius, Molly, or Marcus it is very easy to play a wide variety of models.