If there are no cut outs in cross member take the bolts out or maybe just loosen the mount bolts .Jack up the tranny You made need a 1/2 inch universal socket. You may want to take these bolts out 1st and take the side bolts off last. Also removing the flywheel cover will help greatly. Check the mount looks like it could be contaminated from oil. In one of the pics I see silicone was used...not a good idea unless may be it is perfectly dry and sets up for 24 hours. You shouldn't put the silicone on the outside of the case you are not getting to the source of the leak. A dry clean gasket is always better . Make sure both surfaces are clean an no old gasket is left.
My first questions is did you already drain the transmission fluid? If not, your going to have a big mess once the trans pan breaks free.
I noticed in one of your pics that there are two holes drilled into the underside of your trans cross member - directly in front of the large access hole/slot to your trans mount bolts. Do these two holes line up with another set of two holes that are on the top of the cross member... and if so, are the holes located under the trans pan bolts you are trying to remove?
If not, you will probably need to loosen (or remove) the cross member to trans mount bolts and also remove the cross member to sub-frame bolts so the cross member can be moved towards the rear to gain access to the two trans pan bolts. After you loosen/remove these cross member bolts, you will need something to slightly lift the transmission to take the weight off of the cross member. If you are lifting the transmission by the pan, be sure to place a flat piece of wood between the jack and the pan so you do not damage the pan.
After slightly lifting the trans, you should be able to side the cross member back to gain access to the trans pan bolts. Once you have enough clearance to access the last two pan bolts, lower the trans back onto the cross member (the trans should still rest on the cross member's transmission mount). You should not have to remove the cross member. If you have not yet drained the trans fluid, only loosen these last two pan bolts and "break" the trans pan free of the transmission towards the front of the trans. Be sure to have a large fluid catch pan under this area (it's still going to be somewhat of a mess). After the trans fluid drains, remove the last two bolts and remove the tans pan.
Once you replace the trans gasket (you may also want to replace the trans filter while you have the pan off) and reinstall/tighten the trans pan bolts, slightly lift the trans again to reposition the cross member to its original position. Install the cross member to transmission mount bolts first... but do not tighten them yet. Next, position the cross member so you are able to install all of the cross member to sub-frame bolts and get all of the washers and nuts installed. Lower the trans back onto the cross member and tighten all of the cross member bolts (both at the sub-frame and trans mount).
Remember to refill your transmission with fluid before starting the engine. I always put a piece of blue painters tape (with a note attached) across the the ignition switch as a reminder... as sometimes I get sidetracked and forget where I left off :doh: