The evaporator coil for the A/C is right behind that frozen panel. That much frost would indicate a frozen coil and is not normal. Since the compressor and A/C lines were just replaced, the problem may be with the installation/charging of the system. The air has to blow over the coil for both both warm and cold, so if the coil is frozen solid, no air. If it was mine, I'd first check the blower. It's just to the right of that frosted panel under the glove box and is held on (facing up) with 3 bolts. I recently had mine out to clean out a mouse nest. If the blower is not working, that would cause the frost buildup on the coil. Of course you could hear it trying to work if it was running. You might check the blower fuse too.
I don't know about the seal leak on the front diff/axle. I've never had any oil seal fail suddenly and completely; they have all gone bad slowly over a time. On the other hand, if the diff vent is plugged tight and the pressure builds up on a hot day, maybe an old seal could leak more quickly?