Yes they can defy logic for they have full command to the laws of logic and for you question, everything that exists is ruled by some sort of law and can be commanded by this power and under Absolute Law Manipulation, it says that The user has the power to make, change, destroy or redefine any/all kind of rule/law, including physical, scientific, magical, divine, metaphysical or conceptual, granting them control over all limits, including their own. You pretty much control everything, so it is infinite, for you also control the laws that govern infinity as well.

Lets say someone had Omni-Manipulation but it wasnt at its full potential. A user of absolute law manipulation could manipulate the laws so that laws dont apply to them and then the power/capabilities of their omni-manipulation could be infinite?