Does Infuse respect “Low Data Mode”?

For example, when tethering with iPhone or on cellular.

Not quite sure what you are asking here?

Are you asking if inFuse will refuse to play over cellular or something else?
Since inFuse does not do transcoding the bitrate it uses to play anything is determined by that of the source material

At this time, there are no changes in Infuse if low data mode is enabled.

For example, pause fetching metadata, artworks and Google Drive updates while in Low Data mode, when the user is only watching synced shows.