yup, soft wood on top of a hydraulic jack to gently support the engine. i dont like supporting the weight of the engine on the oil pan, but it is a rigid honey-comb reinforced aluminum pan.
you have to remove the engine mounts from the heads. the right mount is just bolted to the side of the head, the left mount sits on the leftmost head bolt round stud.
so yes, both engine mounts must be removed in order to remove the heads.
you will have to loosen (not remove) two bolts on the a/c compressor. with the compressor a bit loose, you can wiggle the engine mount out.
another way to hold the engine up, is to have it in park, roll the car back a tad. This will pull the engine vertical. Then make sure the wheels can't move and hold the engine in position