to create a hold.
step 1: select the controls select the entire animation set for the controls you want to "hold" still.
step 2: select half of time. hold down the shift key and wave the mouse to the right and left over the motion editor until you see the frame you like. with the shift key still held down, drag the mouse to the right until the mouse moves off the motion editor window. this will create a time selection, as the mouse moves off the window, this will anchor the infinite time selection and select all of time after the frame that you started draging from.
step 3: create the hold. hold down the alt key and wave the mouse cursor over the edge of the time selection at the playhead. as you move the cursor to the left of the playhead you should see the cursor change into a flat line with two arrows on it. this is the handle to drag out the in-falloff for the time selection. since the aly key is held down, doing this will also effect the selected controls motion. click and drag to the left. your animation should be holding still inside the falloff.
step 4: smooth out the transitions in and out of the hold. select the time region at the borders of the hold and use smooth, round etc to make the transition look more gracefull. don't forget you can select different controls and alt drag the time selection to stagger the motion making it so that everything doesn't move at the same time. (aka twinning)