(4) The sort of T- or paddle-shaped shadow around the baby and extending down below the baby will be difficult to fix, but Tools -> Paint Tools -> Clone can easily improve some of the dark spots. IMO this is best done with the view set to 100% or even 200%, the tool's Hardness set to maybe 50 or 60, and its Opacity set to somewhere in the range of 80% to 100%. You can also try similar techniques to fix that almost-horizontal scratch or whatever to the left, and various other scratches or hairs or whatever. My work here was relatively quick and clumsy--with patience it could certainly be done better.