I liked the player piano covers of modern songs in S1. They've done a couple things like that in S2 (the sitar version of "Seven Nation Army" in Rajworld, and the Japanese flute version of "Paint It Black" in Shogunworld, to mirror the player piano version that the scene was a mirror for the Saloon Heist in S1E1). I don't know if you've noticed, but the jingle with the Warner Brothers logo at the end of each episode has been replaced with a player piano rendition, except for "Akane No Mai" which was done using a Japanese shamisen. Not sure why they didn't do the Rajworld episode with a sitar. They missed an opportunity there.
I found this wiki after looking for WW info. It's a great source! After I watched S2E1 I went here to look for details on it, saw there wasn't much, so decided to put it in myself. Everything so far has been pretty standard wiki stuff, which I've done before, so didn't take long to get up and going. More of just looking at previous episodes/seasons to see what names/styles etc. were previously used, and copying those.