Clickable scroll wheel works fine, it is mapped to the same button.
I can't, however, imagine left+middle chord on modern laptops, there are not that many laptops (mostly ThinkPads as far as I can tell) that have three physical mouse buttons.
i'm (happily!) using acme on macos. works great, the option and cmd buttons act as modifiers for middle and left button (execute and search).
BTW, does chording work well with mice where one of the ”three” buttons is the scrool wheel?