I like variety and Lianna has been a game changer for me so I don’t think you’ll regret maxing her first. I think she’ll be more useful in a variety of other situations, not just AW.
What @Math4lyfe said. For blue tank raids I put Margaret in the middle as well. Keeps them safe from snipers and Evelyn/Lianna will finish off whomever you want in one fell swoop. Kingston is great but I get more use from Lianna
Hmmm… If you currently only have 6 tonics, it’ll probably take another few months to get another 6. I think you should choose Lianna unless you’re patient enough to wait for Kingston, who is also a sniper.