How to change an input type (parameter - variable) based on another one? (Wildcards)

This is a bit of a hack, but it looks like you can typebind any number of params together using The SetParam meta specifier.

UFUNCTION(BlueprintCallable, Meta=(SetParam="Arg1|Arg2|Arg3"))
static void Foo(int32 Arg1, int32 Arg2, int32& Arg3);

You can even have multiple groups of params, groups are separated by comma.