I have ATF cooler lines running on either side of the oil pan. They get kinked in the metal clips that hold them in place. I had to cut mine and slip both ends into a hose and clamp it off on both ends. I plan to replace the hard line some day. It's holding for now, though.
Do you have a Hayne's manual? It would come in handy.
Brake pads come out easily, just pop the pins out (or remove set pins, then pop out the pins) and they slip right out.
To remove the rotors, unbolt the calipers from the hangers, hang them with wire hangers, then they come right off. After the wheels are off, that is. If they are stuck, the e-brake might be sticking - or they might be rusted on.
Tranny is pretty simple. Leaks usually happen because of over tightening the bolts and bending the pan. (Check the fluid hot, running, in park, and level.)
Squeak might be a ball joint? Check the dust covers.
Make sure you torque the AT pan bolts correctly: 7 Nm for the 722.0 and 722.1 trannys and 8 Nm for the 722.3/4/5 trannys. You’ll need a 5 mm Allen key for the AT pan drain plug and torque converter drain plug.
Make sure you get MB anti squeak paste, it also helps keep things clean. If you have ATE calipers buy new anti-rattle clips as the old ones can fail after a while.