i would have thought it is alqaab and ahkaam since they are arabic words in origin and in urdu we tend to also use the arabic plurals for arabic words. alqaabaat would be adding an urdu plural ending to a plural arabic word!!
carrying on from http://www.sunniport.com/masabih/showthread.php?t=2361, what is the plural of laqab? is it alqaab or alqaabaat? similarly, hukm. is it ahkaam or ahkaamaat?