First of all, thanks for the mod: I have found it incredibly helpful recently. The one thing that seems to be missing is a search bar for the station selection. Please do add it if you find time.
Aye I've had a look round the lua api but as I suspected it seems the searching needs to be custom implemented and ideally it'll need a bit of a cache for the search itself -- so leave it with me.
I've added a search bar to the replace station screen for the replacement only, from playing around that seemed the most useful and applying the filtering to both the search and replacement wasn't great