Law:
Handbook is an exam oriented book. This is good for revision purpose.
Main Text book is an exhaustive book which contains all the case laws of CA / CS Final exam which is very useful to understand the concept.
Audit:
Padhuka covers the whole Study Material in Q/A format. It covers Study Module, Compilation and RTPs. Once you finish this you don't need to refer anything else for this subject. "Fast Tract Reference" given in Padhuka is extremely helpful for revision.
Surbhi Bansal is very concise and exam oriented book.
My suggestion :
Law - Main Text book of Munish Bhandari.
Audit - Padhuka.