Alright, so just tried it with two different files, and it works pretty darn well. The only issue I had with it (and it could entirely be from me being a noob and not adjusting something proportionately) was getting the 2D item to be in same 3D position as the null object I exported from Modo. The item is aligne perfectly to the camera, but I had to mess around with the anchor point to get it to line up. Otherwise, it couldn’t be simpler, and the guy has a video that walks right through the whole process.
In modo, it was giving me an error that the film back didn’t match the frame size. Was simple enough to adjust (by changing the Film Back setting in Modo). I’m assuming you can get it to work with any frame size, but I’m not sure if me using a non-standard video size (it was like 1344×732 or something odd) was causing that to happen. I switched it to 720×480 frame and it went through fine.
I didn’t get a chance to try out and 3D trackers, but after work I’ll give that a shot too.