Once you get all the bolts out of the t-case, use a pry bar carefully, to slide the t-case off. Be careful to not let it drop cause once its free it will slide off quickly. Don't forget that after you get the t-case off you will want to use some wire to hold the driveshaft up so you don't stress the joint by letting it hang down.
The topic of stripped oil return line to pan bolts has been discussed a thousand times. You can either clean up the threads with a tap or you can have someone weld on a -8 fitting so that you never have to worry about stripped oil pan return line bolts again. The trick to no leak there is using a new clean gasket. ....or an AN fitting.
Use the search function on this forum by using a + in front of the words: +oil +return +line