Just vanilla JS unless you've got prior experience because any engine you use is going to have a setup process and bootstrapping code and a learning curve for you that will eat into your time. Across the weekend you might only really have a few hours to dedicate to this project and to hold their attention.

Using the "memory" game as an example, do you want the problems you solve to be how to shuffle the cards in a random order, or do you want to be solving why the cards all positioned weirdly because PhaserJS defines an anchor "origin" point in objects and by default that's x 0.5 / y 0.5 which means 50% width / 50% height aka the center of the object so you need to either set their origin to x 0 / y 0 or factor that into their position by subtracting half their width and height, and their width and height has scaled and unscaled values too width vs displayWidth... and of course if you're using a group for the card's display objects, that class does not support setting the origin.