I had a problem importing an .ma file from boujou, although I think the reason mine didn't show was because of a graphics card error.

To get your image sequence to show up, go into the attribute editor of your image plane, should be in the imported group somewhere, and browse to the destination of your image sequence.

Your second question all depends on the quality of your track, if you have a decent track then you should be able to put an object in the scene, place it to look like its on the ground, etc, depending on the shot, and it should appear to 'stick' to the ground.

Chris