Technically midi to alac conversion is possible, in sense of making new .alac audio file based on MIDI instrumental music. Maybe this can be done for some very specific reason, but in most cases .midi files are exported just as MP3 or WAV files, considering that MIDI files are very small on their own.
In any case you might need to first use some tool to create WAV from MIDI, before you can turn the wav into .alac as it is very likely that not many tools can be used to convert midi to alac directly.
Updated: August 14, 2023