New Lawn and Flower garden

i have recently laid some topsoil and then turf over the top.  it has taken quite well however there are a few small issues with the actual grass.

There are a few small 'bald' patches where there isnt any grass coming through, a few scorched areas and a some lighly browned areas (as well as a lot of green) - could you give me any guidance to address these 3 issues with my lawn.

Secondly - i have an area of hard 'mud that i have turned over and de stoned, i wanted to put some soil over the top to then have it as a flower garden, could you advise which compost or topsoil would be best?

thanks all