have you used the playlist in FL? you can play multiple patterns with it. i'm pretty sure FL will play back a midi drum role...simulating one would require some type of delay plug in.
You can do a "techno" drum roll by adjusting the volume on each note of the roll. Click on the button immediately to the right of the Shuffle slider and use the volume edit option.
You can have two snares play in the same place by adding two snares to the step sequencer then highlighting your snare hits so that they're vertically aligned in the same column.
with the two beats in one space thing, i want to do drag notes which is two notes in the space of one. That means doing one snare on 1st beat and 2nd snare half way into 1st beat
not sure if I've understood you correctly, but you might be able to do what you're talking about using two snares and the Shift function. This is found at the same place as the volume "editor".
I listened to the MP3 - then pulled out my copy of Pablo Honey for another listen. Can't help you with that drum roll. I spent quite a bit of time trying to simulate just that kind of drum roll in Fruity, mainly adjusting the volume of individual notes. But I gave up when everything I tried came out sounding like machine-gun fire.
Maybe a short delay might help. Can't think of anything else.