Lise and drinking wine in front of an alcoholic: considering that she didn't believe Garibaldi (with reason) about being able to handle his renewed alcohol consummation, I assumed she did it deliberately, too, both to test and provoke him into admitting he needed help. Which didn't work, but nobody ever accused Lise of being a great planner.

...and yes, I also love the scenes with Londo, especially Delenn's hug - and the fact that Londo has no idea why.
Actually, in a way it seems to be less that of Judas kiss than the opposite. When Judas betrays Jesus, they both know what he is doing, but the others either do not, or (in that case of the soldiers) are informed by the kiss. In this case, Londo is pretty much the only one who does not know.

Oh, it definitely doesn't work as as a parallel - which is why I said "an element of", but I couldn't think of a mythological, historical or religious image that fits closer. It's a gesture that expresses fondness - and is sincerely meant that way - but at the same time Delenn is also aware she's washing her hands (ha! another not really fitting image) - of Londo, that tomorrow he won't be an ally anymore but an enemy.