DEAR TALHA BHAI
WELCOME ON CAR CARE THREAD 
for black re-painted panels first need wet sanding than compounds , polishing , wax coat etc
if i am at ur place i would use following products ( sure for repainted panels u have to do first wet sanding etc )
1) ok mothers car shampoo is good
2) mothers clay bar kit also good
3) instead of mothers rubbing compound i would prefer meguiar's ultimate
compound due to its ease of application and very good outcomes
4) for polishing my choice meguiars ultimate polish , u can apply this polish to any color
OR if u have da or rotery polisher than try 3m machine glaze for dark paints its specialized polish
( yes its polish so dont go on its label ) this is only good for dark paints and remove minor imperfections
5) yes mothers step 3 paste wax good for dark paints
step 3/4 correct paint light scratches, swirls and provide best base for finishing wax , if u can live with scratches and swirls than yes u can skip step 3 and 4
claying process remove years of oxidation , clean the surface from contaminations and provide very sleek , clean paint surface like a new born baby skin , its totaly safe for car skin
