I would suggest that you use the SHARE menu to share the movie to iTunes.
Once in iTunes, you can play it through home share.
If on the other Mac, you find the Movie in iTunes on the original computer, you should be able to drag it to the Movies section of that computer's iTunes. The whole iTunes section (movies, TV, Music, etc) should turn blue, and that is where you drop it. It should land in the Movies section.
Once it is there, you can sync it to the iPad.